Tobold started it, and since my comment was running long, I figured I would post my response here.
AoC sold around 750k units, and most attribute that to general MMO boredom. Since AoC really did not deliver all that it promised, many MMO gamers are still in boredom mode. Add those in with the large number of people who outright avoided AoC, all those burned out on WoW and looking at WotLK as more of the same, and I think a ‘safe’ bet is 1.5 million copies sold before 2009, with perhaps the upper limit being 3 million. 3 million however would make WAR a huge success, but I certainly think the market is capable of such numbers.
The big question of course is what happens after. If WAR delivers on the promises of RvR goodness, that number should continue to increase as word-of-mouth spreads. If that’s the case, I can see WAR reaching the 3-5 million mark in 2009. If RvR and WAR in general has some glaring flaws, expect the numbers to drop to around 500k subscribers.
After the first year, WAR’s success depends on how well Mythic continues to add and balance content, and just how much pull RvR has in keeping players interested. If DAoC is any indication, RvR done right certainly is more than capable of keeping people paying and playing.