I think this is a concept that plagued Spore to some degree; the scope of the game's concept was simply too huge to comprehend. To simulate the creation and evolution of an entire species from a single celled organism to a space-faring race of technologically advanced beings is a fantastic and whimsical endeavour to say the least, and yet that was what was promised.
Obviously the course of several million years of evolution had to somehow be squashed unceremoniously into 30+ hours of real world gameplay, and this effectively resulted in several disjointed minigames that tried desperately to mimic several other popular games, while at the same time offer a (slightly stylised) depiction of real world mechanics, biology and society.
The very idea of somehow simulating the advancement of an entire species simply isn't plausible; at least, not until the "civilisation" stage. The rest of the game is crippled by it's own scope. The thought of simulating the evolution of an entire species using gameplay mechanics instead of _actual accepted evolutionary fact_ (if I kill this creature, I can slap its mouth on everyone in my species? Darwin would be rolling in his grave). The truth needs to give way to gameplay sometimes, but I doubt we're ready for even a stylised simulation of evolution on Spore's scale yet.
I never got to the space stage, by the way. I wanted to create a peaceful, religious (peaceful, ha) race, 'cause I'm soppy that way, but I found the civilisation stage was balanced too much in favour of the military and economic races, and I was bored by that point anyway.