Oh god please... Not this again! Go to the mod forum, somewhere in there it gives a good explination. The many different mods reflect the many different taste of people. While Juggy seems to want to throw everything in, someone might want to focus on Jedi, or another on aquatic combat (dunno why, just throwing out an example.) Now some mods can mesh if they're just adding a new unit or planet and don't try to make a whole new game (commonly referred to as Total Conversion mods, or TC mod for short.) You might get a mod with everything in it, but at least some people will be un-happy with it and try to make their own hence all the different mods.