For the sake of not letting the hype blind me, I haven't spent much time studying Age of Conan in advance. I'd rather play the beta, starting tomorrow hopefully, and see for myself. But while I don't read the AoC official site, I do read blogs, so I can't help but get some information from there. The best source I've found up to now for Age of Conan commentary is Keen and Graev's Blog. While I had to sign an NDA to get into the open beta, Keen says the NDA was dropped for participants in an earlier AoC event, which I find confusing, and somewhat ironic, given that Keen once chided me for breaking an NDA a few hours early. So he has not only comments on various AoC feature announcements, but also first-hand experience tales directly from the game.
Anyway, in his latest post he is talking about AoC's battlekeep vulnerability system. In other games in which guilds can conquer keeps, like DAoC, those keeps often change hand at 3 am, when the owning guild is sleeping and the attackers organized an early bird raid. In Age of Conan the owners of the keep can choose themselves at what time their keep is vulnerable to attack, and the attacker has to sign up for an attack at least 24 hours in advance. If several guilds want to attack, only one of them is chosen to be able to do so, based on PvP points.
As alluded to in the title, the result is somewhat silly. But the obvious advantage of a vulnerability window system is that the defender is far more likely to be actually present when his keep is under siege. That is an interesting reversal from a general MMORPG PvP situation in which the attacker only attacks at moments where he is sure the defender is weak, like people ganking somebody in a fight with a mob, or PvP objectives being attacked at odd hours. The disadvantage of that system is that once the strongest guilds have conquered the keeps, of which there are only very limited numbers, it becomes very difficult for anyone else to ever take them away. Battlekeep possession could easily become rather static, and thus uninteresting. If the defender is forewarned and thus forearmed, the game system has to somehow give the attacker some other advantage to make a change of ownership of the keep more likely.
Well, in any case this isn't likely to affect me. Any system in which PvP guilds conquer keeps, which will be the case in AoC as well as in WoW, automatically exclude casual players from that part of the content. A pickup raid group is more likely to succeed killing Illidan than to capture a keep from a PvP guild. And as I managed to avoid military service in real life, I'm not keen on joining a virtual military organization in a virtual world.