talking hypothetically here myself, been proved wrong too many times with such assumptions to be sure.
but if they have the beta by October we could sure hope for a release late February/March.
first quarter 2011 is only possible if the 5th class is fully playable at Blizzcon this year and they start the beta till late October max. then we'd have to wait for second quarter i'm afraid. good thing is that at least it wont require as much testing as Starcraft 2 to balance.
but if they have the beta by October we could sure hope for a release late February/March.