I just happened to think of something after talking about fatigue in another thread.
I came up with a system whereby the people in your party got fatigued by wandering around carrying large amounts of items, thus making it realistic in the sense that you can''t walk around for 3 weeks without sleeping.
However, this would be
totally unnecessary in a game where there was no day or night.
So then I got to thinking...some games have day and night, but I''ve never seen it implemented to its full potential. (Given I haven''t played as many games as you all have, and most of what I HAVE played was old NES/SNES stuff.) I''ve never seen a game where certain shops are closed at night, or some important NPC you need to talk to is asleep at night, or maybe some other important NPC you need to talk to is ONLY awake at night. (Maybe he''s an astronomer, or he likes to go out in his back yard and dance around naked casting spells.) Realistically, you could even have different critters that come out at night vs. what wanders around during the daytime. I mean if you''re gonna have night in your game, there should be advantages & disadvantages to both day and night, otherwise there''s no point in bothering to make the distinction at all.
So then I happened to think...what about seasons? I''ve yet to see a pure RPG that has seasons either, or at least not graphically represented ones. (Simcity & Simfarm don''t count.

) Imagine if your magic system uses reagents, how hard it''s gonna be to find some herb in the winter. You may hafta go all the way to some southern city to find them still in stock or growing in the countryside. Maybe you hafta put on snowshoes to be able to travel fast in winter, or maybe you can even ski. Maybe you need to talk to some NPC who''s a shepherd but he goes to a warmer area whenever winter hits so his sheep don''t all die. Maybe various places have holidays during certain times of year, during which time some shops are closed but other shops sell celebratory items and people dance in the streets.
Then I got to thinking...seasons would be great for strategy games as well. In the winter, your farms produce no food so you''d hafta hope you had enough stored up, or have holdings far enough south that food could still be grown and your armies wouldn''t starve. Traveling in snow could be difficult for some military units, and you could perhaps manufacture skis or snowshoes or somesuch to equip them with to make it easier. In the spring, some rivers could flood due to snowmelt, and not only be harder for your military units to travel across, but also possibly threaten your cities/military bases and population if you had them put in the wrong places. Perhaps in the hot summer some types of troops would fatigue easily and be much less useful on the field.
Anyway, just a bunch of stuff to think about.