With Blizzard planning to release "DotA" for Starcraft 2 with the new expansion pack and League of Legends sporting 2 Blizzard employees who also originally worked on the DotA project (AFAIK), I'm not sure that DotA 2 would do all that well... LoL racked up almost 1 million unique views on the streams the past weekend at Dreamhack, breaching 210k simultaneous viewers today... with many Blizzard-like elements rolled into 1 package it would be interesting to see what they can bring to the party (so to speak)
But I fear it's too little too late and they'd have their work cut out for them to catch up with LoL's popularity and Blizzard's attempt at it for SC2