I don't think the event is poor. It's important lore, and it's a battle in which the players have a chance to participate. When the attacks occur, the leaders assemble their forces and drive it back; they aren't going to let it burn just because no wandering adventurers show up. Then we all head to Northrend to deal with it at its source. Well, maybe it is a poor event if you are only interested in your personal advantage. But as part of the continuing story, it's great.