I think that there should be some new classes.
Medic- would have medic packs that replace grenades, would have infinity packs but take time to regenerate more.
Sniper- would have a better rifle that would do more damage and take longer to reload,also have a scope that can some in w/ 3x optics.
I think that there also should be more guns and maybe customize of your character.
More suggestions-
- Side arms
- Vehicles
- unit customization
- parachutes
- Gun mounts ( MG's, Cannons )
- And more