Can there be a possibility that tank (or at least the crew) can be destroyed with a hand grenade in the hatch ‘coz in reality that is one of the ways to destroy the crew of a tank. That would make tank crewmen to ask for infantry support to cover them because in current version tanks just stand in the middle of enemy army and kill anyone in sight. (AT can’t really damage them too much) Besides I have had many situations that I’m standing ON enemy tank and I can’t do anything to it

even with a grenade

Maybe the hatch should be closed and it could take some time for infantry to open it.
Or for example if you kill a gunner that was sitting in the hatch then hatch would remain open and vulnerable for an attack.
Sorry for my bad English.
P.S. I searched "tank grenade" and found nothing sorry if this already was suggested.