Blizzard just announced that parts of Wrath of the Lich King content will already be released "in the coming weeks" in a patch that will presumably be called patch 3.0. So we get the new spells and talents, barbershops, new arenas, guild calendar, and the inscription profession in advance, for free. Death Knights and Northrend you'll have to wait and pay for. Not a huge surprise that, they did the same with patch 2.0 before The Burning Crusade.
But many people interpret the patch announcement, and the new features that were announced for Wrath of the Lich King and which just happen to be similar to features that Warhammer Online: Age of Reckoning has, to be a defensive move by Blizzard. Are they getting nervous of losing a million customers to WAR? Well, they would be stupid if they did nothing. Even Age of Conan cost them subscribers, even if they said later that 40% of those came back.
I wouldn't read too much into specific announcement or release dates, nor into specific features. I don't think Blizzard conjured up Lake Winterspring in a week because they realized they needed keep siege warfare to counter WAR, features like that must have been in preparation for a long time. Who can say whether the inspiration for the new WotLK achievement system was WAR or one of many older games already having that? And frankly, stealing features from WAR wouldn't even be a good strategy to fight it; the WoW keep siege warfare and achievement system will naturally be inferior to the WAR one, because they weren't integrated into the game right from the start. If WoW wanted to really hurt WAR, they would have to announce features that WAR doesn't have, like player housing for example.
Anyway, I'm happy if both the Blizzard developers and the Mythic developers are well aware of their competition. I hope it will make them work harder and better. Especially Blizzard was a bit too complacent about their invulnerable market position. Competition in the end is always good for the customer.