Having a driver that can shoot means too many 1 manned vehicles , which would create vehicle spam on the scale of PS2 or greater which is bad if you want good infantry fights with lots of melee
Gunner: I've sighted an enemy tank, I need an AP shell, it's got low health, quick Loader: Я люблю морковь и суп из картошки! Gunner: What? no... Er ... Tank-Ah pierce? Loader: дёрп Gunner: Look, just get out the tank, I'll find and English speaking crew man and we can... Loader: Старкрафт лучшая пони! Gunner: No I mea-. *BOOM*
The main gun should be used by the gunner only, if the vehicle has a small front facing gun I don't mind if the driver can use it, otherwise he should just drive the it. Also switching seats inside the vehicle should take few seconds, during this time the player should not be able to do any action (drive or shoot depending which seat he was in).
could have a load out of commands press 1(AP) then he would receive the Russian version of the command load out
The main issue is that unlike driver and gunner, loader is a horribly boring seat. You basically wait around and twirl your thumbs, then press one button every few seconds. You could make some horrible QTE minigame out of it, but that would mostly be annoying and unnecessarily complicated. With how many different guns most 40k factions put on their tanks, we'll have plenty of crew slots with one driver and a whole bunch of gunners.
