honestly, i've played WoW for ... hmh, 20-25~ active Months in the last 5 Years, and everytime they launched a new Patch that changed or fixed the mechanics, i didnt think of anything bad. balancing is great, and if they continue to improve player satisfaction by doing so, all should be happy. (tho' i of course had a moment or two where i was cursing about other classes.)
shortly before i stopped playing, i started wondering.. "why didnt they achieve equal class effectiveness by now?" but then i thought about how complex the mechanics actually are, and continued tolerating the issue(s)..
..but yeah, i thought they would have learned from the Mammoth that is WoW, and therefore make a greatly balanced game with Diablo, setting up mechanics accordingly and stuff. And in addition, 5 classes shouldnt be too hard to balance properly.
i didnt play the game yet, i was honestly considering a purchase though.. but reading about how they didnt seem to get it right (once again), pushing numbers around to fix what they didn't manage to do properly, i start wondering,... who the heck is testing that sheat while its still in development? i mean, seriously?