since there are many class suggestions out there, i thought i might throw in my own ideas on the subject, this is an EXTREMELY simple class system
3 new things here:
Medpack: drop on ground, will despawn after 2 minutes, once picked up by a teammate it will bring their health back to 100
Supply box: drop on ground, will despawn after 2 minutes, once picked up if any teammate is low on ammo, blocks it will bring both ammo and blocks to regular
Pistol: does 40% the damage of the semi, and has less zoom and range.

Assault(SMG):smg/2 grenades/50 blocks
Sniper(Semi):Semi/2 grenades/50 blocks
Medic:Pistol/2 medpacks/50 blocks
Support:Pistol/2 supply boxes/80 blocks( blocks take 4 hits to take down as opposed to 3)

Here are a few additional game modes i would like to see:

Control points: pretty basic, if you have played other team-based fps, you'll know what i mean, there are 5 randomly placed(unless it's a custom map) control points on the map, 2 belong to blue and they are near the blue starting area, and 2 near the green, 1 is neutral in the middle of the map. each side has about 100 reinforcements, reduce enemy reinforcements by killing them and capping cps. each control point also has a resupply which will provide resources to the team that has the control point, neutral resupplies, provide resources to neither team, control points also serve as a spawning area so you can choose a friendly cp to spawn in before rushing into battle.

Aow(all out war): i would like this added if aos ever gets 64 player servers, basically this i just a massive team deathmatch, there are no control points or flags, just kill or be killed, there is 250 reinforcements for each team in this mode. There are also a few things exclusive to this game mode, there is a person called the team commander who is elected after 3 minutes in the battle depending on votes from the team (you cannot vote for yourself) the team commander has the authorization to use 1 of the 3 special abilities available to your team:
1: Support: when selected this brings up the map and choose an area, when chosen, any friendly players within the area will have their health,ammo and blocks instanly refilled.
2: Offense: when selected brings uo the map, when chosen, it will send 5 artillery shells into the area after 5 seconds of choosing the area each shell has the same splash damage as a grenade (though it does 5x5x5 block destruction) and will explode on impact with a block or player, so make sure to aim correctly.
3: Defense: when selected brings up them map when you choose the area it there will be a large force field wall that will stay for 30 seconds and enemy players cannot walk or shoot through it, useful for making an escape.

The commander can also monitor other team members' health,ammo and blocks.
The game ends when one teams reinforcements reach zero.

thats my suggestion. please dont leave harsh comments and offer some constructive criticism