SC2 or New Expansion?

Personally I would rather see a HUGE expansion to starcraft instead of seeing a whole new starcraft game come out, the graphics in the game are already fine, the physics are perfected and I dont know how they would be able to duplicate it in SC2.. drop micro would be impossible to do in a 3d version if you ask me so I would just like to see a new expansion wit a new race and a few more units/buildings to each race