Believe me, having the people doing all the work listen to feedback is at LEAST twice as awesome as getting feedback on work that you're doing yourself. And I really, really appreciate the time this whole mod community puts into this game. It's fantastic, especially for something this early in development.
And yeah, DPM/FPM aren't that great as overall indicators of weapon balance. Especially with things like the mass driver that thoroughly break the mold of expected characteristics for a given weapon type. Not only is it's range immense, but it's projectile speed is incredible. And neither are things I'd want to be nerfed too badly, they make it incredibly fun to use. I think the best areas to nerf the mass driver are in OP cost and rate of fire, and possibly upsizing it to a large slot. MAYBE range could be nerfed, but an extremely fast projectile with very low range looks pretty ridiculous. And you don't want to nerf it's speed/range or per-shot damage significantly, because that's the entire appeal of the weapon, and what makes it unique vs. the vanilla weapons.
And that's a hard thing to balance! Keeping weapons both very fun and satisfying to use but also very balanced isn't easy. The hadron accelerator is INCREDIBLY satisfying, and certainly not useless. It's long chargeup time, enourmous hardpoint and OP investment to field it, and the associated amount of babysitting it needs to be used effectively (the AI is still hopeless with it) mean that it also isn't overpowered, despite having incredible burst damage, range, and accuracy/projectile speed. It's a fun weapon to have in the game because everything about it is decisive - the player feels like it's a significant decision to mount one on a ship - feels like it's a significant decision WHERE to mount one on a ship - and feels like it's a significant decision WHEN to fire the damn thing once it's on the field. That's the kind of weapon you want, where it makes the player feel like the decisions he's making with regards to that weapon, and as an extension, the game as a whole, actually make a difference. That's FUN.
Damn, that turned into a ramble. Hmm. Me go make things to pew-pew in space.