The forums have become more vitriolic of late, I'll concur. It could be because we're bored while we wait for the next patch. It could be because we all have some discontent with the game, and none of us can agree on what the source of that discontent is. It could be that there is a growing chasm here between elitists and us "filthy casuals," and both sides forget that the other is also human.
Things could get better once 3.5 drops, and they could improve dramatically when 4.0 drops. It remains to be seen.
Web forums tend towards toxicity unless they are moderated pretty strictly (I've been on a lot of forums in my day, and this is pretty consistently true). As awesome as the moderating staff is here, they are not very strict (and nor can they be without substantially bolstering their numbers, and establishing some kind of due process for moderating decisions that can exempt them from legal recourse).