This is a massive problem that Blizzard doesn't seem to be rushing to fix and there's many reasons this could be happening. It doesn't matter if you're looking forward to WotLK Ulduar or if you're trying to find your WotLK Class Guide if Blizzard doesn't get on top of the current issues in the game.
In this video I talk about a few contributing factors to the most recent Wrath of the Lich King situation that many players are talking about and where Blizzard may be falling short in terms of what they can do for Wrath Classic.