Mmm, I think that as long as the tank retains its stubby gun, it actually makes more sense this way. If the tank commander is killed, then the aura given should technically be nullified, no? Makes sense from that regard; but yes, Gameplay > realism.
Whoever enters the command tank automatically gets promoted to captain and is able to use the special radio equipment to direct his troops using his newly found sense of command... even if that man is a soviet conscript.
Seriously though, what is the difference between the stubby gun and the p4 long barrel? Is the stubby gun more for anti-infantry?