I'm surprised nobody's said this, but I also think some abilities need to be reworked. It's not just the weapons that need changing, but I think stuff like Respawn Punisher and Special Charge Up definitely need to be looked at. Basically, the abilities that have the most impact on the battlefield, like Damage Up/Defense Up and MPU used to. There are quite a few meta builds right now that I feel need to be toned back. There's not much point in nerfing weapons if abilities can just basically undo them with enough AP.
Everyone forgets abilities exist because only two or three are unbalanced. Maybe four. Or five, at most.
Thermal Ink is stupidly easy to fix, all they have to do is make it work for AoE damage.
Respawn Punisher is bad, but there's no real way to make it better. It needs to be reworked or removed, and that's better done in the transition between games than in balance patches.
Tenacity is still nearly useless, but has some options to be improved. My favorite idea is for the ability to give 10 AP of Quick Super Jump to players who jump to the user, following the niche of being good for weapons that don't die.
The stackable abilities are all fine with a few exceptions for specific Sub Power Up or Special Power Up effects, and those are basically just sub/special buffs at that point. Actually, no, wait, Intensify Action still sucks on weapons that don't have shot spread.
Intensify Action should slightly reduce mid-air charge time, and slightly increase jump height for all weapons.
That should be everything worth men- no, wait, Opening Gambit exists.
Opening Gambit should only lose its effects 10 AP at a time, so if you don't get any splats or assists, it'll grant 20 AP of each ability until 45 seconds into the game, and 10 AP until one minute into the game.
That's all of the abilities that need balancing.
If you're worried about gear abilities' impact on the meta, a good solution is to reduce meta options' gear freedom.