Lightmaps or Real-time
I wonder sometimes what the percentage is of players that really want a dynamic time of day that's always changing, or if they don't really care one way or another.
From my own point of view as a player, I know that I'm mildly annoyed when the sun is moving so fast that I can see the shadows quickly moving across the ground. I also find that since games almost always speed up the day cycle in games, that night seems to come too often, and is frequently too dark, and let's face it, it's annoying when you can't see where you're going.
I think I'm just as happy with specific times of day that have been done really well, and are visually interesting. It's probably a personal preference thing.
As far as the lighting you do, you'll be at the mercy of whatever has been decided from a technical point of view as to which you'll be using.
The "good news" about a system that uses deferred rendering and no lightmaps, is that you don't have to wait for the lightmaps to be rendered. Nor do you have to be involved with lighting UVs Once you've lit the environment (or the cinematic) you're good to go. The "bad news" about a fully dynamic lighting system is that it can be difficult to get nice soft shadows and bounce lighting, both of which are available to you when lightmapping.
When you're lighting in a system using lightmaps, you've not only got to render the lightmaps, you've got to re-render them anytime something gets moved. It "breaks" the lighting. On the other hand, you can use as many lights as you want with no limitations when you're rendering lightmaps, including the use of area lights.
So while they can be slow to render and sometimes a bit tedious to work with, they can give very nice results.
