Depends. The expansion is coming out March 2013, and HotS requires Starcraft II Wings of Liberty to play it. So unless you're keen on buying both and spending ~$80 for a game, then go for it.
A lot of ppl sorta just dropped out or became inactive. I'm one of them. The game just got really boring for me, especially since i have to click every fuking 5 minutes.
PM me if you want my acc....