They DO fire on the move, its just that activating the ability halts the tank, meaning you have to re-command it to move.
Yeah that's what I meant. Fire on the move - fire the smoke while moving instead of halting. I guess since they never changed it it's an example of asymmetric balance. But the range isn't so great, so I rarely use it - you can't cover an assault with it all that well in my opinion. If the range was slightly greater I could live with the halt.