Every MMO studio has its own particular style and flavor. You can argue that the game itself matters more than its point of origin, but that doesn’t feel completely right; for better or worse, no one other than Carbine Studios would have made WildStar, you wouldn’t expect World of Warcraft from a team aside from Blizzard, and it’s pretty clear that CCP Games is very much the sort of place that makes EVE Online. And that also leads you to some expectations about what a game from a studio would look like: Even if both CCP and Blizzard had a license to make a World of Darkness game, they’d produce very different MMOs.
But let’s put the license and IP to one side to ask which MMO studio you’d like to see make another MMO. Sure, Blizzard may have consistently not done this for many years, but maybe you’d like to see it take on a second full MMORPG. Or maybe you want to see another title from Daybreak or find out what happens if Grinding Gear Games switched those gears to working on a full MMORPG. Don’t worry about the setting and all that, just figure out which studio you’d like to see in the driver’s seat for this sort of speculative venture.