It's a class. The entire personality archetype and job of the character are completely different. My character is not a fighter in any regard, he doesn't use two weapons, he would flee from combat rather than fight, and I'm not going to change my class for that minor of a reason. I can take racial substitution levels as a kobold rogue that very accurately work towards the theme of being a trap specialist, the high number of skill points works well, and it gives him the sneaky edge needed to get away from a fight.
Besides, we're not an adventuring party, we don't need to work towards some sort of theoretical group balance. I want to play a rogue, so that's what I'll play.