Possibly - but I don't think the graphic styles really match up with what StarCraft would have.
Oh and to clarify, those that left Blizzard North will certainly be a blow - but it doesn't rule out the possibility of another Diablo game. Blizzard North still exists, is still owned by Blizzard, and still has the ultimate rights to the franchise. Only four or so people left Blizzard North (including Bill Roper
) so there is still a substantial team left over. They're currently working on the Diablo 1.10 patch - and I'm sure there is another project in the works as well.