WHAT?! You need more reason than finding that class 17 bomb first among all the races?? I guess some people just don't feel the urge.
There's something to what you say though. My biggest gripe, since I opened my very first game in GC2 in fact, is the way every player's so damn uniform. So it's not the map that's undifferentiated, but rather the strategic layout. The range technologies are particularly anticlimactic. If your origin were identical with a species or two, then the extra 5 tiles might actually mean something. As it stands, you have to have 4 levels more (which in this case sadly requires a tech "age" or two as well) before you even feel a difference.
Of course for that to change, this whole game needs to become a rather different game. [begins talking about when GC3 was just an announcement] For example what if you could settle a world together, with another race. So sharing star systems and sharing planets in some cases. The role of influence on such planets would become to divert resources, so it's not a half-and-half planet, but gives more to one or the other owner. There's 1000 ways to set this up, and every one is better than "race colony ship towards planet, lose or win by 1 turn, late colony ship turns around and flies onwards for 231894123809 miles."
I'm going to start on a mod right now that takes life support out of the trees altogether (I'll make speed techs provide the modules instead). J/k, I'm really lazy. But to sum up, XWerewolfX has a point. There is some need for spicing up here, and plenty of room as best as I can tell!