Well if you compair the Warcraft franchise vs the Starcraft franchise especially in the Asian Markets, they would be all over this.
Now even if WoW lost half of it's subscribers to Starcraft, even at 4 million it's still a win win either way. With most MMO's getting a max of 250,000 subscribers, they can't loose money wise.
Honestly I wouldn't mind Blizzard pumping out a few MMO's and putting another nail in SOE's coffin.
Yeah that might take 7 years to make, but at the same time you are getting a very polished game. None of this Stalker Crap.