I'm going to start this one off with a simple disclaimer: I don't want to hate Call of Duty, but I do. I used to be a fan of this game, back in the mid-2000s. I entered it with the first Modern Warfare, I gave up on it with Modern Warfare 3, and I developed a deep and lasting resentment for the franchise when Ghosts came out. But ultimately, no matter how much I hate what the series has become, how formulaic and paint-by-numbers it is, and how it has completely refused to innovate, I never wanted to and I think that the right game could immediately bring me back into the fold. I also don't think I'm alone. While it's easy to say the franchise doesn't deserve saving, I definitely have my moments when I think that, I would be happy to see it change and go back to being a good, innovative series like it was for a whopping 2 1/2 games in the 2000s. I know it seems strange to say now that Call of Duty was ever good or innovative, but it was for a brief period of time and its fans, while a bit stubborn for sticking with it after years and years of samey garbage, aren't entirely insane. (Though that level of dedication seems at least a little crazy to me.) So, tonight, I sat back and thought about what it would take to make me stop hating Call of Duty, and go back to being a fan. (All of this also applies to Battlefield, an equally vapid series for all the same reasons that could also employ this exact strategy to fix its issues.)
The game, as it is, needs a a new setting, and a new feature tied into it that completely changes the gameplay in practice, without seriously changing the gunplay or the controls. Something that would allow old players and current players to pick up the new game and immediately intuit how to work it, but would make the game new and interesting, and give the game more depth than it has ever had. (Because honestly, we weren't there for deep gameplay in CoD's golden era, we were there for the stories of Modern Warfare 1 and Black Ops 1.) That's... Hard to do, I know, but there are ways that can be done. I came up with one example, because I'd be loathe to say "you need to be more creative" and not to try being creative on this issue myself, and that's the following: Powers. Set the game in a way that special powers and abilities would be available without disrupting the seriousness of the franchise. Maybe paranormal would work, but more likely we're talking about a science-fiction entry that adds powers of some variety. They need to feel really sci-fi, they should be entirely from gadgetry but as long as they give a very wide range of effects and have a profound gameplay impact, they'll do the job.
I kinda played around with this idea, and I have an example pitch for what such a CoD game would be like. It's just one idea, and while it is pretty detailed I'm not saying either that this idea is perfect how it is or that this is the only thing that could possibly save the franchise. Nor is it complete, Call of Duty and Battlefield have far more issues than just staleness and a lack of innovation. The handholding, the inconsequential nature of combat, the cutscene-heavy and gameplay-light gameplay, the lack of any real challenge, the gunplay having actually lost the weightiness and active participation they used to have for mega-ultra-auto-aim that lets you just point vaguely at the enemy and win, they all need addressing too and they're honestly more important, but most of that comes down to "backpedal 12 years. For the idea of how to make the games fresh, hear me out.
The Premise:
It is the year 2218. You are part of a secretive post-human special forces unit. Officially, you do not exist. But in reality, you are deployed to tackle tough situations stealthily using advanced technology, psychic powers (insert handwavium, neural-connected projectors in your helmet, whatever) and personal robots for covert operations. After a brief training excercise where you practice stealth, gunplay, telekinesis and control of your robot (basic tutorial), you are deployed on a mission to Generic Rogue State to permanently shut down a research and development operation there. But when you arrive, you find they too have psychic soldiers... Which shouldn't be possible. And they're just like yours... As the game goes on, you uncover a shadowy corporate cabal, which sold state secrets to rogue nations for profit, part of a tinfoil hat worthy worldwide conspiracy. Then, you find out your own organisation and your own superior officers are involved, and they try to have you killed. You are forced to escape and go rogue for the last act, and are labelled a terrorist by official sources during the credits. It's not a super original plot, but it's reasonably interesting, fits the tone of the series and has room for some impactful moments. (If the conspiracy's revelation isn't memorable, somebody did something wrong.)
The Features:
The principle differences that would shake up the gameplay come from the futuristic and paranormal aspects of the setting. They're incorporated in such a way that although they have a major effect on the setting and on gameplay, they are believable and the 200 year timeskip allows them to be more futuristic than magical, so returning players can suspend their disbelief. However, what these do for gameplay is not insignificant and they come in four categories: Psionics, robotics, suits and weaponry. Health would also need to either not regenerate on its own, or regenerate extremely slowly. In single-player, that may be determined by difficulty.
Psionics:
Psionics are your super-handwaved psionic powers which must absolutely NOT be magical. Maybe it could work if it's paranormal and unexplained, but I think a scientific-sounding premise would work far better on the core audience, and on sci-fi fans whose genre you are entering and who you are trying to court. I believe it's important a good handwave be implanted here, it doesn't matter much what it is as long as it fools the standard audience of Call of Duty games (which isn't very smart) well enough, and elicits a chuckle from science-fiction fans. Say you've got a neural connection in your helmet and your suit that allows you to simply think your commands, and there's force affectors in your suit. Exactly how the neural connection happens, and what these force affectors do to create the results, that doesn't matter at all. As long as you have a cohesive premise as to how it works and have put even a little thought into it so it makes sense to some super basic extent, you've already done enough to maintain your audience's suspension of disbelief. The illusions are holographic, and read your thoughts through your neural connection to produce images through projectors on your helmet. The force field uses a shield generator in the palm of your suit to create a millimetre-thin field of high-temperature magnetised plasma to reflect projectiles. The telekinesis uses zero-point energy through its nonsensium projectors to technobabble enemies away from you. Just think about the premise enough to create a basic "this does this" diagram for your descriptions with some vague notion on how it maybe might work, and you don't need to figure out the details. After all, in the lore 200 years of figuring this stuff out happened to create these technologies.
These powers take over the grenade buttons, meaning you can have two powers equipped. These share a regenerating psychic meter, and more powerful abilities have a higher cost. Remember to handwave this. If you can avoid it don't even name the meter and your players will name it for you, but if you must name it remember this power needs to not be magic and find a non-magic sounding name for this. AC, affector charge? I don't know. Activision and Treyarch can focus-test this and I can't. Even an indie studio has the time and resources to come up with a good nonsense name that says "not magic" to the fans of this series, and says "look, it's not supposed to be magic, but we're trying" to the sci-fi fans this title will catch the attention of.
These psychic powers, or suit abilities, or whatever, include extrasensory perception, illusion, telekinesis and support. ESP abilities let you see through walls, mark enemies on minimaps, highlight enemies and dangers, and see through illusions, amongst other things (the more diverse the power set, the better). Illusion abilities let you turn invisible, create visible duplicates of yourself, darken or cloud areas so they can't be seen through, blind enemies with a flash, create sounds that will distract enemies, and so forth. Telekinesis lets you force push enemies, manipulate physics objects a la gravity gun, grab items (ammunition, med kits, grenades) from a distance, and create barriers that deflect bullets at predictable angles and can even rebound them directly back at the shooter (the more direct the shot, the less damage the bullet does when it's reflected). Support, finally, allows you to provide buffs that increase your allies' speed, make them take less damage, or can even heal them.
These powers all interact directly with the gunplay, and many do so in what could be an interesting manner if well handled. For example, you can defeat a twitch shooter that surprises you around a corner by projecting a barrier when you see them and reflecting their gunfire back into their face. Or you could force push them off a roof, probably not killing them but dealing damage and ending the encounter. Or blind them with a flash and backpedal around the corner, buying you a couple seconds to figure out what step 2 of your plan is.
And don't forget, for the really active ones, draw some connection to the player using it. Create some visible effect for the nonsensium forcefield pushing enemies with force push, find out what works best. Maybe just a visual blur effect on the space affected by it. Good visual design will help reinforce the idea that this is technology, not magic, and keep the players immersed while allowing you to do what you want.
Robotics:
Robotics are also both a meaningful feature that shakes up the gameplay, and the kind of thing that made me like this franchise back in 2006: Customisation porn. The robot is small and man-portable, fitting on your character's back so you can deploy or collapse it at will, and in multiplayer you get to customize it as part of your loadout. Start simple with stationary robots, ground-based robots and flying robots, and go from there. The player decides what weapons they hav, how they're armoured, what utility systems they're given. You could make a heavy-duty turret that has a machine gun and self-repairs, or a flying sensor bot that has detects enemies and carries a laser, or perhaps a walking medical bot that both protects and heals you, all by changing its base-type and its loadout.
CoD players by and large love to customize their loadouts, and giving them yet another thing to customize helps sustain their interest. Not to mention it's genuinely useful in gameplay, and the fact that every player has a custom, portable military robot means instead of being an unfair advantage or a kill streak, it's a core part of gameplay. A good, well-customized robot that suits your playstyle can make a huge difference. A sniper will be happy to have a robot spotting for them, marking enemies on the map and warning them if somebody's sneaking up on them. A rusher, meanwhile, would probably like a flying medical bot to keep up with them and restore their health after gunfights. And at the same time, the robot is separate and vulnerable from you. If you die, your robot might avenge you. And if your robot is shot down, you're a lot less capable without it than somebody with their robot would be.
The Suit:
Suit options are pretty straight-forward. You can add armour (damage resistance, countered by penetration), shields (small layer of regenerating HP), carry more utility items or change your sidearm slot into a second primary weapon slot, or change your primary weapon slot to a special heavy weapon slot so you can have a larger, more powerful weapon than you'd normally get. In exchange, your character becomes heavier, and less mobile. It's pretty straight-forward, but if well played it can potentially be pretty deep. It's been a while, but I remember Tribes did okay back in the day. Also, making armour only resist like 5% of incoming damage would be shameful, it needs to actually do something, and pairing it with penetration is a good move as it adds a lot of depth.
As an example: You can have a base resist of 0%, 25%, 50% or 100%, but each will slow your character more than the last. Every rank of penetration reduces these by 10%. That is to say, with 0 penetration a shotgun is reduced 0%, 25%, 50% or 100%. With 1 penetration a 9mm pistol is reduced 0%, 22.5%, 45% or 90%. A 7.62 battle rifle with 5 penetration is reduced 0%, 12.5%, 25% or 50%, a .50 BMG with 10 penetration is reduced 0%, 0%, 0% or 0%. That means certain weapons are more valuable based on their efficacy against armour, even if their other characteristics are lacklustre. It also means armour becomes an active consideration in gameplay, and shapes your playstyle. A heavily armoured character probably sticks to cover and never goes out into the open, since they're a slow easy target to snipers their armour isn't great against, but the shotgun campers they're likely to encounter in cover are going to fail hard against their armour.
Weaponry:
And weaponry. The series has always had a diverse set of weapons, despite some of the fans being insufferable (part of why I left) and insisting only SMGs and assault rifles are fair play. I vote to expand that weapon set, using the sci-fi setting. Keep the ballistic firearms, all of them, largely as they are. (Maybe make the shotguns not have a range of two feet, and provide different shotgun loads, like slugs and flechettes.) Melee weapons too, quick melee button shouldn't always be a knife. A hatchet, or a sword, or a bludgeon, they could all have different effects to make them a bit different. IE: This knife is just really fast so you get the quickest quick melee, but this knife does more damage and this one instantly kills if it hits an enemy in the back. Or you can get a short sword that does more damage but is slower. Or a hatchet that does good damage and is good against armour but it's even slower. Or a club that's really only good against armour (maybe ignores it entirely). Variety is the spice of life and all. I think Black Ops III had a variety of melee weapons, but I've never played it. (I haven't played a single CoD game since Black Ops II, and haven't owned one since MW3... Which was a mistake to even get.)
But the big one, the new one, would be energy weapons. If we're 200 years in the future, you can do that. If you want more variety, make it 300 or 400 years in the future. I can see a good variety already. Pulse lasers that are perfectly accurate, hitscan explosive snipers, but have a long cooldown so you need to make a shot count. Beam lasers, which deal very rapid DOT with splash damage, but overheat quickly and create a big glowing trail (from atmospheric blooming) that leads right to you. Electrolasers, which aren't that strong and are slow semi-automatic weapons with overheat, but they're lasers (thus perfectly accurate) and they cause the heaviest flinch of any weapon type by far (making it very difficult to shoot back, since you keep being knocked way the hell of line when they hit you). Coilguns, which can be quick-shot as a very slow sniper of average power, or charged up several seconds for an incredibly powerful shot that will one-hit enemies with a shot to the chest and penetrate every wall clear to the far side of the map. Maybe even plasma weapons and ion weapons, slow and short-ranged with travel times, but plasma weapons are powerhouses and ion weapons deal okay damage and murder energy shields.
More than that, existing weapons can get new features. Okay, I have a noob tube. But does it NEED to be a frag grenade? Maybe I want a HEAT grenade that has a teeny blast radius and really good direct hit damage. Maybe I want an incendiary grenade. Or an EMP grenade. Okay, I have a scope, but maybe it can have a built-in rangefinder so I can more easily adjust for travel time (if that's even a thing in this one), or thermal vision, IFF, a directional microphone, X-ray vision, get creative.
So, why do I feel the games need more weapons? Partially it's just because while the variety in-game is actually pretty good as it is (that has NEVER been an issue), it can be improved and the game would only benefit. Additionally, a sci-fi setting doesn't just allow powers and robots, but it allows you to easily improve the weapon variety without breaking immersion and it'd actually be LESS immersive not to add some new, advanced weapons. Energy weapons in particular allows you to use very game-y mechanics for your weapons, like the travel time of a plasma weapon or the overheat on lasers. That's GOOD, it's good to find ways to expand your mechanics without challenging immersion, and I don't think a player sniping with a gauss rifle is going to think "hey, the charge up here is a really game-y mechanic, like the Sniper in TF2 and Widowmaker from Overwatch", they're going to be kept in the experience because their weapon makes sense and blowing a fist-sized hole through another player's chest across the map through body armour, a refrigerator and three walls is a satisfying culmination of their skills, their weapon and the x-ray vision power they chose. They aren't going to be thinking about the game-y ness of their robot helper either when it shows a flanker on their minimap, they'll be too busy switching to their pistol and setting up to fight them off, using that couple seconds to hope they can win the fight when the opponent likely has a superior close-ranged weapon to their simple handgun.
Conclusion:
Is this idea perfect? No, of course not. Does it fix the largest problem with the genre itself beyond how stale the two lead series are? No, the creepy level of handholding, insultingly brainless "gameplay" and crazy linear "cinematic" campaigns with no actual gameplay will take a lot more than this to fix. Is it going to get the purchases of all of Call of Duty's diehard fanbase? No, but if they're still here in 2018 they're loyal enough to at least try it. Is it going to attract back all the people who abandoned the franchise? Hell no, some people who used to love the series now hate it too much to ever be brought back. Is this the only option to save the franchise? Not even close, it's just the best idea I, personally, can come up with. Is this even the best approach? Maybe, maybe not, I can't say. But something needs to be done or this once noble and now fallen franchise will die forever, and this WILL win back far more people than it loses. I think this, or more likely something else creative just a little bit like this in the core premise ("add new features that radically shift gameplay without changing the core gunplay, and is accessible to old players"), is the best bet for the series going forward.
But then, what do I know? I'm broadcasting thoughts on how to save a dying AAA franchise I only used to like to a game development forum where it will never, EVER reach the people actually in charge of the franchise I want to see return to making games that are good, fresh and interesting. I'm even such a loser my idea is basically "You need to do something REALLY new that doesn't change it too much for your existing audience to enjoy it, here's one way.", and that's the most obvious advice in the world. Take what I say with a grain of salt.
PS: If you're thinking "Well, Activision is beyond hope, but an indie shooter using this model could do pretty well.", you have seen through my ruse. Congratulations.