--Standard Mass Driver--
Primarily used to suppress and kill lower HP, faster targets. This works in the widest range of situations as it doesnt approach the extreme in really any area. Overall pretty solid and I wouldn't suggest any changes.
~Average Direct Damage
~Average Splash Damage
~Average Splash Radius

--Assault Mass Driver--
The NUKE EVERYTHING gun. It's low DPS makes it difficult to kill things in direct encounters but it's exceptionally good at suppression and locking down a large area with constant DPS. Works amazing on large clusters of enemies and hitting enemies behind cover. Again I don't really have many issues with this variant.
~Low Direct Damage
~Low Splash Damage
~High Splash Radius

--Breach Mass Driver--
This is the problem child. Currently crappy splash damage and radius with a decent amount of direct damage. This weapon basically requires you to get direct hits to do any meaningful damage...and if I wanted a weapon that required direct hits, I wouldn't be using a Mass Driver. I think the more appropriate approach is to keep its tight splash radius but have that equate to a focused blast, thus having much higher splash damage with a low splash radius. This would be the variant most oriented at direct 1v1 combat due to decently high DPS (though splash DPS should still not exceed that of a direct weapon such as an Assault Rifle).
~High Direct Damage
~High Splash damage
~Low Splash Radius

Also Swarms as a Heavy only weapon? I can only seeing it make sense as a Heavy side arm which would be Bad Azz.!Heavies have no ammo replentishment if solo, can see it killing swarms completely unless it's a heavy only sidearm..

I'm all for seeing a sentinal firing forge shots and swarms at me.. that's av dedication

Mass Driver with any AV capabilities should be garbage vs infantry unless it is a direct hit. 400ish damage with 1m splash, like 4 in the clip. Would be garbage vs shields but do 2000 damage to armor per clip with bonuses per clip.

Also all rounds fired from all Mass drivers should damage the user of said Mass driver as most people that use them deserve to suicide.

I think that swarms should work like the Large Missile Turrets, no lock-on with minimal splash damage so that they won't be effective against infantry

Except for when I dumbfire a payload down a hallway or into a crowded doorway.

I can also do it with a forge gun and nobody's complaining

Swarms were dumbfire once back in the long long ago.

And it was TERRIBLE. Imagine firing a plasma cannon that launched four mass driver rounds at swarm launcher velocity. It needed to die then and it doesn't need to come back now.

Besides this thread is about the mass driver anyway...