Personally, I just can't see it happening unless there's a considerable redesign of multiple aspects of the game. Creep spreading is just bad for gameplay, hydras are trash without it, and roaches are so one dimensional.
There's also a lack of hard counters, and not nearly as much unit variety, and less potential for extremely well controlled units to pull off near-miracles. (Terran has a bit of this, at least). Just the design of the game seems off... it's like they didn't want any units to lose too badly to any particular unit, because it would scare off the noobs if their marine army got decimated by 2 lurkers in that one second they looked away.
BW is just so perfect... it's crazy how well a game like that turned out. It was kind of a fluke, they couldn't have predicted how many things would be figured out about the game but still have it be so well balanced in the end. You just can't replicate success like that.
I think SC2 will do well, there's incredible hype about it now and the expansions will keep people hooked for years... it should definitely outperform WC3. But to remain a popular competitive game for an entire decade? Ehh... it's not impossible but I wouldn't put my money on it.