well ppl have their opinions, the only games I count as 'kiddie' are Sesame Street street learning games and the likes..
Spore in particular is NOT a kiddie game once it comes to the Space Stage...
although, I would've preferred it to be less cartoony than it came out to be.. if you find videos of the game in the developmental stage, it allowed for more variety to make more serious looking creatures (still a bit cartoony) and you had the ability to construct a skeletal structure, there was blood and you could make creatures that lived under water (I assume also that you could develop all the way through the stages even underwater, that would've be flippin insane)
why they decided to cut all that out.. iunno, but I'm gonna lay the blame on pressing publisher demands to simplify the game (I'm lookin at EA here...)