CharlesGrey: If you do some research and add in some actual historical events and facts, your game would even be educational. :)

Just make sure to pick a setting or theme you'd really enjoy, so you don't grow bored with it. If you use the time travel or alternate dimension concept or something like that, you could have multiple completely different settings, to keep things interesting for yourself and for the players.

Or how about you have several different time periods or settings, with different main characters, but all of these episodes/chapters are connected in some way. You know, like in Eternal Darkness, if you've played that. That could be really cool.

Licurg: Try a mix of it, Fantasy and Sci-fi, something like Warhammer .

Smannesman: I've actually recently read two genre mixing fantasy series, one post-apocalyptic and fantasy and one semi-modern and fantasy, if done well it can be interesting.
It certainly spices up the predictable fantasy genre a bit.

eyelessoverseer: Thank You. But I'm afraid not many of the players would be interested in economical parts of history and that's what I focus on when reading history books. I hate all those battles and dark politics, but I may be able to keep my jaws strongly shut and just get into the more attractive (for others) history facts and events.

CharlesGrey: I think it's important for a game maker ( or any artist/creator ) to focus first and foremost on what they enjoy and are interested in. Just make a game you would like to play; what others may or may not like is secondary. If you worry too much about that, you won't enjoy working on your project and it probably won't turn out well. So just have fun and do what you like. :)

QC: Regarding your poll, you have to balance what it is you want to implement with the environment.

Example, you talk about regulating body temperature, health, overall, so forth. In most Sci-fi elements you wouldn't have to worry about that unless you want to go dystopian as you'll have regulated environments and recycled oxygen, water, food, fuel, so forth. You can use that for situations that call for a need of mental and physical stimulation however. Space travel causes a loss of muscle mass and bone density in astronauts if you don't simulate gravity, so they have to do a lot of training and exercise to keep themselves fit for return. You also have loneliness, isolation, which you can read upon the effects of cabin fever to get an idea of what that can do to someone.

Fantasy, health-wise would be more a concern, including clean water, food, heating, hunting, so forth, but mental stimulation is not something that will be of much concern. That stimulation will occur naturally from the environment, the people, their actions, and from a realistic perspective, a majority of persons in the older worlds would have been largely uneducated. That doesn't mean stupid by any means, but only religious leaders would have need to write or read, something we consider so basic in modern days. You wouldn't be learning anything if it didn't help or relate to your social status or job. Learning is going to be much more important towards the Sci-fi route.

Modern Realistic would fall between. Knowledge will occur for knowledge sake, but with the real modern practice and understanding of psychology and the effects of modernization, you fall into risk of depressions, isolation, boredom, struggling between the lack of stimulation and the want or need to act. The further you lean in one direction however the harder the opposite happens. One who exercises heavily will be less prone to laziness, but more anxious by their inactivity. A book-heavy person will want to read, and not feel comfortable without a book. Psychology will be your heavy focus if you go this route, between situations of activity, social action, financial ability and preferences towards certain activities. This route requires however the most work as you need to have more variable effects than the others from wealth, enjoyment, shyness, Social Need, age, and the environment growing up (Be it more rural or industrialist and urban) along with pre-existing mental issues such as depression. Then you'd have to develop the system to act at different time rates or variables for certain values (Example: High shyness and high social need means there's less benefits of speaking to people with more effort. A low social need means you less often need to interact with people, but the shyness may also cause a negative impact on mood)