This suggestion makes actually sense. Though not in the form it was suggested.
A QQ forum won't help anything, because nobody QQs. Everybody is only making valid points and suggestion to fix obviously broken stuff, which is in no way near to QQin/whining.
Rather call it "feedback" forum, and make precise rules about what to post where. For example your topic should meet certain requirements, if you want to post it in the balancing forum. You should involve a few values and some good argmentation, just comparing the damage values of two weapons and saying that the one with the higher value is OP because... it has a higher value won't be enough.
Opposed to that everybody is allowed to describe his personal perception, his feeling and emotions in the feedback thread, concerning the way his class plays, the way he dies by other classes and so on. I guess this can be a useful help for the developers, but even if it's not, it will at least provide us with some funny thread