Honestly I'd imagine another MMO very simmilar to WoW would and should be the last thing on Blizzard's mind, all it would be is shoot with guns,lasers and spines/spikes/goo and kill x/y enemies, the Starcraft series started out as an RTS and yes while Warcraft had done so as well that franchise branched differently, that doesn't mean to say that a Starcraft MMO will 100% be a smash hit and work, it would likely be stale if anything to transform a popular RTS franchise into an MMO.
If anything I;d want Blizzard to come out with a new Warcraft RTS seeing as how the RTS genre has been in a steep decline for the past 6-7 years and could really use a company like Blizz to bring the genre back in a big way, hell a Diablo RTS would be interesting with the 3 factions being Nephalem, Angels and Demons.
Mankind, in its arrogance and self-delusion, must believe they are the mirrors to God in both their image and their power. If something shatters that mirror, then it must be totally destroyed.
