Apart from the pure Warhammer Online blogs, there is a distinctive feeling in the MMORPG blogosphere of people becoming disenchanted with WAR. Even Heartless_, who calls himself a WAR fanboy, now says that he'll leave WAR in three months if things don't get better. In a way that cycle of pre-release hype, and post-release popping of the hype bubble isn't anything new. But hype is only a distortion to players slowly revealing their true preferences.
The problem with the MMO market in the last months was that it was dominated by "bored with WoW" players. They bought Age of Conan, they bought Warhammer Online, they bought a lot of other games. But November 13th many of them will buy Wrath of the Lich King, and be back to World of Warcraft. And in early 2009 we will see some of them being bored of WoW again and looking for other games again. But at that time WotLK will still be relatively fresh, and there won't be any big new hyped game around, and players will slowly tend towards the game they like the most.
While it isn't immediately obvious if you only look at level 1 characters, at their core World of Warcraft and Warhammer Online are two very different games. That becomes most clear in the end game. It is hard to find a good description of the two different end games which doesn't use any terms that might be considered judgmental. But the endgame of WoW is one of PvE, and the endgame of WAR is one of PvP. In WoW you repeatedly fight raid bosses with various abilities and in various surroundings, but these bosses act on a script and are ultimately stupid. In WAR you repeatedly fight other players with a limited scope of abilities and always the same fortress / city surrounding, but these opponents react in a far more intelligent way. Both endgames have their advantages and disadvantages, and thus their fans and detractors. Some people simply prefer the one, some people prefer the other. The discussion of which one is "better" is about as pointless as discussing whether strawberry ice cream is better than chocolate ice cream.
While the motives of individual players might differ, on the large scale we can assume that people who prefer PvP will drift towards WAR, and those who prefer PvE will drift towards WoW. The two games together will totally dominate the US / European market for MMORPGs. And it is interesting to see how PvP fares against PvE when you give players a choice of two games with similar high quality, but different basic gameplay concepts. It appears that PvP in the western MMORPG market has a significant share, but there are about 4 times more players who prefer PvE. Worldwide the PvE to PvP ratio isn't all that different, after adding the Asian players of WoW and games that are big in Asia like the Lineage series to the count.
So I think PvP games will have a solid future, because somebody will always figure that its easier to go for the 20% of PvP players than competing with many others for the 80% of PvE players. I don't think we will ever see a game that makes players of all types happy, there are some fundamental incompatibilities between perfect PvE and perfect PvP. Perfect PvE means continuous advancement of your character in power, be that in level or gear. Perfect PvP requires characters being not too far from each other in power level, so that factors like skill and organization have a chance to influence the battle. I don't think that we will ever see a situation where PvP games have a larger subscription base than PvE games. There are simply too many people around who prefer to fight only against the game, not against the other players. I wish WAR the best of luck, and I am quite happy that it managed to give people a good alternative to WoW, but personally I prefer PvE games too.