Replaying this a bit, this time trying to experiment more with stuff I didn't use.
I gave Cerberus a more thorough try and yeah, it still sucks. It's not even the lack of damage (even though that's important), but it's the lack of utility that kills the weapon. No launcher, no decent stinger like equivalent, small AoE for its attacks. There is no reason to use it over A&R except against element weak enemies. In SM it's a bit better but Cristal and its CC are basically the same as A&R and Flicker does really pathetic damage (and doesn't change in the air version like Nevan's Air Slash). Ice Age is interesting, since this game has really few iframe moves, but it's too clunky to use. Honestly they should have upped the damage and stun and made Crystal into a normal move.
Artemis is interesting. It's basically free damage: the weapon. Its normal shot against a single target does 70 damage (which isn't bad considering it has good range and can also be used in the air), and the multi-target shots do 50 and can hit everyone. In terms of DPS is decent, but GS is crazy. The GS shot basically gives you 400-500 free damage every few seconds or so and Sphere+Acid Rain is nothing to scoff at either.
E&I are also suprisingly good in GS. Alternating between normal shots and Twosome Time increase your style meter like crazy and even Rainstorm does good damage (around 300 on a single target if you mash hard enough) and crowd control.
Shotty is good but I have to study Fireworks more, since it seems only useful for cancels instead of its intended purpose, which is to be a get off me move. Gunstinger also has the most DPS out of any Stinger-like move in the game. Don't know how much damage the followup does, have to test this (since the pastebin seems to have some inaccurate stuff, like Charged Shot for the Shotty which does around 200 damage instead of the 130 the pastebin claims).
KA's grapple is cool and also does decent damage, but I'm not sold on Hysteric. I've seen some mention that it has some uses but I don't see them tbh.
Finally we have Nevan, a weapon I never really used that much. My interest in the weapon resparked after I saw these on Youtube.
https://www.youtube.com/watch?v=Ss0tDF-oDHg&ab_channel=vul4akhttps://www.youtube.com/watch?v=f7GEymDbs_U&ab_channel=vul4akEvery physical attack brings Dante into the default stance, so you can chain everything fluidly. It's also great for buffering and in general does good single target damage (Combo 1 does 300 with the bats and 100 with the shockwave, while Combo 2 only summons the bats, but you are then free to switch weapons and the bats will still hit the enemy you've locked on to). I like how easy it is to buffer Drive with Nevan, made me use that move much more.
After this I will experiment with Doppel and QS a bit, before doing a full GS playthrough.