Looks like locks are the biggest QQ'ers in the history of WoW:
Moment 1:
WoW is first released. Hunter and warlock pets could be one-shot. Hunter dps was pretty lackluster. Soulstones gave you rez sickness (I think). No soulshards from PvP. The first emo whiners in WoW were born:
Hunters and
Warlocks. World of Roguecraft video is released showing how a rogue in crap gear could wtfpwn people while warlocks were so gimp. Result is that warlocks went on to get buffed in nearly every patch as they were on their way to god-hood. No more world of roguecraft videos. Hunters saw substantial improvements as well, but weren't made into demigods.
Moment 2:
Mages with both Talisman of Ephemeral Power and Zandalarian Hero Charm could stack the trinkets' on-use effects to drastically increase spell damage. Coupled with Arcane Power and PoM Pyro, such mages could one shot almost anyone. Massive QQ on the forums ensues. Result is that trinkets no longer stack such on-use effects (one exception was a glitch that allowed Hex Shrunken Head and Skull of Gul'dan to stack, but that was later fixed).
Moment 3:
Before Burning Crusade, the best PvP gear was PvE gear. Raiders in tier 2 and tier 3 gear ruled the Battlegrounds. Massive QQ from
casuals ensued. Result was resilience and arena gear without any rating requirement for the first few seasons in TBC.
Moment 4:
TBC is released. About a month later as most people hit 70 and begin running level 70 five mans and heroic dungeons, it becomes apparent that druids are one of the best tanks if not THE best tanks for 5 mans. Massive
warrior QQ ensues. Result is that druid tanking is drastically nerfed..
Moment 5:
Alterac Valley is redesigned. Suddenly, Horde are winning on average 80% of AV games on most servers based on forum estimates. Massive
alliance QQ ensues. Alliance boycott AV. Result is that the Horde starting zone in AV is pushed further back and Balinda is buffed.
Moment 6:
Blizzard toys with the idea of nerfing lifetap on the PTR. Before the nerf is even implemented on the PTR, massive
warlock QQ ensues. Result is that the change is never implemented on the PTR and thus never got patched into the actual game.
http://www.wowinsider.com/2008/07/10/forum-post-of-the-day-moving-moments/