I have an early 15" MBP and have only upgraded RAM to 8GB, SSD is being shipped. Runs on highest res and high settings except shaders on medium and get between 30-40 FPS with non of the reported drops by other users.
Depends how you define playable, and what detail settings you were using. 15-20fps on lowest settings isn't very playable in my opinion. But some people may find it acceptable.