Generally tankers don't go fighting on foot in Ost anyways because all they have is a pistol, whereas tank commanders can still call arty and have SMGs. If you give all tankers pistols only, and disallow them to capture objectives (which they shouldn't be anyway), then tankers will have little incentive to fight on foot, and even then, only to fight off any immediate dangers they face after bailing out, after which they can despawn themselves (with an appropriate delay so they can't just despawn themselves to escape death) rather than continue fighting on foot.
Thouse aren't bad suggestions, as it would prevent people from abusing the tank class as a personal "maximise my kill/death ratio" powerup rather than the teamplay minded class it should be, but it's still a lot of work for little gain.
The only real loss i see from removing tank bailing (once we remove all the silly gamey reasons that where abused in Roost) is the abillity to scout ahead whilst the tank remains hidden, that would be a valid reason to exit the tank, and on tank-only maps (not so much on combined arms maps, as all the infantry crawling about would make it very risky indeed) that can be considdered a downgrade, not a gamebraking one, but yeah, a downgrade.
(as for bailing to prevent death, i see no reason why scuttling the tank coulden't perform that task, all it really must do is preserve reinforcements)
But it's a huge amount of work to make this system just for that, the work that would have to be put into it is far in excess of what i suspect most people realize, on par with all the anim work put into switching between all the positions, and harder to code, it's no small thing that would have to be done here.
