Like aoffan23 has said, 'peaches' are for movie and other licensed themes. Lego seems to think that they better reflect 'real' people in brick form. As such, with all the work that goes into licensed themes, they are tending to end up with alot
of the cool stuff. Especially since all the licensed themes have far more conflict than the average Lego themes. Thus, they get more 'weapons' for such conflict. However, I didn't think you should count the Yellows out just yet. They are getting their fair share of awesome, just in less conventional forms. Or more conventional, depending on how you look at it. Eh, *shrug*
As to the degree of Peach oriented prejudice, just check out the wiki and judge for yourself. There's plenty of posts on the subject.