Gameplay: Simple suggestion: ammunition types utilizing the ballistics system.

[Kriegson]

An additional modification to weapons...assuming they might not have this already. Like various optics you can equip on a weapon, you can equip various types of ammunition with varied effects.

While there have been other threads with a similar suggestion, the difference here is the depth of my suggestion.

TL: DR
Various ammunition types that not only change how a weapon functions, but can also give common pool weapons a more distinct faction feel and ability.

Examples:

Slug -shotgun
Faction availability:
A large, solid projectile with a tendency to tumble, it is less accurate and drops quicker than most conventional rounds, but has a longer range than scattershot and does high damage.

Mass reactive round -shotgun
Faction availability:NC
A solid projectile with an explosive charge that detonates a moment after impact, blowing the target apart from the inside out. It is highly effective against armored personnel, but not so against shields, of which they detonate against.
Also less effective against lightly armored personnel, as it tends to pass right through and explode outside the target.

Fleechets -shotgun
Faction availability:TR
A cluster of razor sharp darts, Fleechets are far more accurate than round pellets and can easily tear a lightly armored target to shreds, though less effective against heavy armor. The cluster of sharp projectiles are somewhat effective at depleting shields, though not ideal.

Pulse round -shotgun
Faction availability:VS
A pulse round is a strange hybrid of both a scattershot, and a slug. After the slug flies for a few brief moments, it fires a spread of deadly radiation in the direction it was originally fired.
Too close to a target, and the slug will strike them, simply doing basic ballistic damage. Too far, and the spread from the radiation will be too weak to do damage.

In the ideal range though, the pulse round can do immense damage to shields, and acceptable damage to living tissues.