I am EXTREMELY skeptical about what I've heard about Titan so far. But then again, who knows if what I've heard is true or not.
WoW was the first and only MMO that actually got me to play. Every other MMO I've tried I felt no need to play past the usual 10-30 day trial period (I'm more of a first person shooter type of guy). So if Blizzard can make something just as good or better than WoW, then more power to them.
I just hope the Activision crew stays out of Blizzard's way. Blizzard is VERY good about releasing some of the higher quality products in the industry, even if it means delaying/canceling games. You can't say that about other Activision dev studios (Treyarch comes to mind at the moment...).