The title explains all
For my opinion
A perk that allows you to run an extra ammo crate (actually 2 would be bettee for a total of 3) this would incentivise the use of crates again because now that pouches refill grenades crates are obsolete but the thing is crates being stationary will get rid of the other classes having to chase down support players as long as the crate is intact i loved thay perk in bf4 and they should proabably make ot 3 crates at once so if only a few people are support amko isnt an issue
The option to put your syringe on the wnd of your rifle like a bayonet (or on the bayonet) realistically this is stupid but i mean you can ressurect your teammates with a little syringe so you know. This would give medics who want to revive some extra distance so they dont have to be on top of their target
Also an extra or twp extra medical crates could work too for the same reasons as support.
This one is hard so i got nothing
a respawn beacon thingy that allows your squad to spawn on it as long as it remains intact.