After many years of inactivity I have just recently over the past few days started looking around this forum again. Its quite a coincidence that this topic was posted just yesterday as it was a major part of the project that I wanted to get started when I signed up at this forum. I'm currently trying to figure out how it could maybe work without the real money economy.
- rant about legal issues you can ignore if you want - (After reading up on the legal issues (I live in the US) I decided I didn't want to risk getting all my assets seized as the kingpin of an illegal criminal enterprise under the RICO act and to go to jail for violation of the bank secrecy act of 1970 and the unlawful internet gambling enforcement act of 2006 (these are the repercussions of the federal government ruling that virtual currencies like bitcoins are real money). There is a book I bought on amazon that sort of covers this topic and mentions second life and entropia quite a bit (before the ruling on virtual currency by the feds) called virtual law navigating the legal landscape of virtual worlds by benjamin tyson duranske if your interested in it.) - end rant -
I am very familiar with entropia universe as I played it quite a bit around 2006 - 2010 right before they went to cryengine. It pretty much ruined my ability to enjoy online games anymore as it just feels pointless and boring without real money being involved. I was one of the few people that never got lucky with a big loot, never put in a large amount of money, never scammed anyone and still managed to make thousands of dollars playing it (it would have been $10,000's if I had started with a big deposit). Then cryengine was announced, it became a money pit, and I quit.
In terms of game design I think a game like this will not appeal to most people however there are enough people that are interested in it that you could have a successful game.
I don't quite get how you say it wouldn't be pay to win though. I mean it is not the typical pay to win where you pay the developer, instead you pay another player or players to "win" or at least get some advantage (unless you only plan on having cosmetic items tradable). I do think this is a better system though. I would rather pay another player who got lucky to get something rare or spent his time to grinding some boring gameplay to get loot I need in a trade then to just pay the game developer but that's just me.
As for in-game economy issues just take a look at entropia. I haven't really looked at it much in years but I remember the massive inflation ($20k+ for a gun, $35k to heal yourself) and the players that cheated early on that have insurmountable skill levels that you can never compete with. At the same time some loot items and mined materials just kept getting cheaper and cheaper until it was tt food. It would be very difficult if not impossible to have a stable economy in such a game but then again I don't think its a requirement either.
"Should such game try to make any protection from out-of-game trading between players?" I would think you legally would have to due to international anti money laundering laws on top of the fact that if your income is from taxing these trades you don't want people not paying you.
If you ever do end up starting a project I would love to be kept up to date on it. If you live outside the US I don't think you will have many legal issues in most countries. Even in the US you would probably go by completely unnoticed but I wouldn't want to risk it.