I have the twisty stick mapped to rudder for tank steering. It's hard to move the stick for aiming without causing a bit of twist as well and that leads to the tank moving off. The only solution is to either not use the twisty stick mapping (i.e. stick with AWSD), use actual rudder pedals and steer with your feet, or turn the engine off (which, as the OP points out, turns "shoot and scoot" to "shoot, dawdle and be blown up").
Actually there could have been one more solution. You can now map an analog axis to a key press in the latest version and I have mapped the right toe brake to W (mid) and shift W (max) and the left toe brake to S (mid) and shift S (max). Then if you hold down your left foot max, for shift S or STOP, you'd think it would keep the tank stationary even with the engine on and turn requested via the twisty stick. Unfortunately, the turn input overrides the STOP input and the tank still moves. This is true even if you hold down the SHIFT S key.