With Mods now coming out with new tanks and accurately crewed tanks, like the Abrams, Leopard and Challenger. The added 4th position in these vehicles now renders the AI useless in a combat situation. The gunner on these vehicles will not engage anything other than infantry and that to is sometimes at a push. No matter what seat the player takes in a modded tank the ability to engage goes out the window.
Adding a recognized 4th position into the actual game itself would allow for modded vehicles to engage and fight properly in a combat scenario, please take this on because I don't like playing a tank commander who has to hop around the tank to fight, it's both impractical and stupid.