yes, let's totally get rid of these realistic and used in real life features. let's take them out of this military simulator.

" at least no recognition between empty vehicle and enemy vehicle " that was the only thing I think is necessary.

This does however impact new players, players who haven't trained themselves and may find it annoying. besides, so what if they added it, would it really affect anyone in anything but a positive or neutral way?

http://commons.wikimedia.org/wiki/File:SDV_Mk_IX_US_Navy_Submarine_Museum.jpg

this (while not being the exact model) suggests that these types of submersibles are indeed not supposed to be watertight.