You shouldnt be able to do everything like you're an ultimate killing machine.
Running away is okay too. I cant wait for a tank to roll up, and for me to actually feel terrified and run into trenches, or look for teammates to help me. Alternatively, if Im an Engineer or anti-tank, I would try to take them out.
I hate how later Battlefield games overlapped classes so much. I remember in BC2, Engineers had silenced weapons, and were pretty much forced to avoid conflict with persons. That was great. Then in BF4, Engineers felt like they could take on people on foot while repairing things and firing RPGs.
I also imagine you'll be able to board vehicles, just not be captain.
Oh you shouldn't be able to do everything, agreed. But getting out of a tank and allowing your opponent's to steal it when you think you're being froggy is rolling the dice which you sometimes have to do. It's part of the dynamics of the game. NOT KNOWING if someone is right around the corner to ruin your day because you did something stupid.
Plus, it's a video game. I'd agree with the whole killing machine thing if everyone was allowed an SMG, lmg, full auto, rifle, launcher, c4 and claymores all on one guy - but that shit ain't happening.
You'll still need an engi to repair and destroy vehicles with ease, still need that medic for kits and revives, etc.
Allowing anyone to use a vehicle won't change that - it adds a dynamic to the game to rolling the damn dice because YOU could be the ass that lets the opponent get an extra tank when you step out or YOU could be the guy to steal one when someone else hops out and win the fight.
This won't stop anyone from picking a class and using the LIMITED spawn vehicles as flat transports for themselves. That will still be a thing to deal with.
This solves ZERO issues and only limits the dynamics of the fight.
A step backwards and then some. Solves nothing, limits how you play.