Because the mechanics of the game change fairly frequently, I think you're going to need some mechanism to "age" answers, or at least indicate what version of WoW the answer is correct for.
For example, if the site had existed a few months ago and one question was "What level do you get a flying mount at?" The answer that was correct from a few months ago would be incorrect now.
Ideally, users would go back through old questions and downvote formerly correct, but now incorrect answers; and upvote new correct answers. But realistically that isn't going to happen very much. All the stale, out-of-date pages on Wowwiki proves that.
I'm not sure exactly how you handle this. Maybe autotagging each answer with the current WoW version, so people can guess if it might be out of date. Maybe slowly automatically downvoting answers. I'm not sure.