you don't need the hatches closed to fire a tank...and a tc can be standing in the hatch with binoculars and giving the order to fire...in a battle it is recommended to batten down the hatches but it's not necessary.
if the tc has fire control at his station, nothing stops him from standing up in the commanders hatch and hitting the fire button...
There are no engagements in tank qualification fired with the TC standing out of the hatch. In fact, the SEP V2 you cant even see straight ahead because of the CROW.
So, back on point, first, I can hit a tank that is on the other side of a mild berm from the commanders sight, but not from the gunners. Pretty sure in all tanks, the commander reticles is a mirror of the gunners. Secondly, If you were in a tank battle and in contact, i doubt seriously you would be standing out of the tank. I know of some of some iraq vets that are missing limbs from being out of the hatch in contact. I never stood up in my bradley in contact. We did not have chicken shields either. TC hatch was turtled if anything to keep happy grenade guys out, gunners hatch closed. We could waste the discussion on credibility. The fact is, it is gamey.
A human, exposed to fire in an airplane is susceptible to being wounded. Not the case in GVs. This is a concession to compete with other games? Not sure. In my mind is simply a way to exploit the game. It is very easy to make a template or hash your reticle to make range changes and shoot exclusively from a position where you are situationally aware. For this, my argument is, there should be a risk and a price of failure.
The fix should be a crew approach to the tank. If the player is wounded or killed by aircraft while in the TC view, he loses that position. He then has to drive around in gunners view, since I think the drivers view with the exception of the WW, have all but disappeared a options. If anything it would make fighting GVs a bit more competitive because guys would maybe fight from the gunners view to cut down on the risk of being wounded.