I doubt it.
WoW is too old and there's more profit in keeping the subscriptions separate. You might get a couple more expansions though. Whatever is in the works currently.
More likely they'll be trying to bank on D4 and Overwatch to start with. Then, maybe, move on to something else.
Either way they'll try to milk whatever newest franchises are out for as much as they can before doing anything. But current WoW isn't likely to be a flagship for anything.