Here are my thoughts but also feel free to help me out
Duelists
Neon - Make it so she doesn't get stunned by her own stuns. As Neon, it's really hard to take space with the stun bcoz you have to wait for the stun to go off, and you're just standing there while it happens. Also make the 2nd bounce for the stun optional (like a sova dart) bcoz a lot of the times it bounces in unpredictable and random ways causing more hindrance than benefit.
Phoenix - His main problem is a lack of movement abilities. Let him have a stim effect (run faster) similar to brimstone's, when he steps in his molly and when he is ulted.
Reyna - Her ult is completely dogshit. Worst ult in the game. Make her invulnerable to detection-based abilities (sova dart, fade dog, raze boombot etc) while ulted. Also let her heal/dismiss even if the soul orb is behind cover. A lot of the times you might get wallbang/headshot-angle kills but simply can't heal/dismiss.
Yoru - No changes imo he's already very overtuned.
Jett - Let her only have 1 smoke but make it last a bit longer. With a dash and 2 smokes, she has a total of 3 get-out-of-jail-free cards. You can make the dumbest plays itw and get away bcoz of the 2 smokes and dash. Would help bring her insane pickrate down.
Raze - No changes but plz fix the bugs with her ult where you shoot someone point-blank and they survive. Overall a balanced agent.
Sentinels
Weakest agent class rn
Killjoy - A common buff for all sentinels should be that damage abilities (Grenade, shock darts, mollies etc) don't destroy the Sentinel utility. You should only be able to destroy them with guns. Bcoz it feels like literally anything and everything will break the sentinel utility.
Cypher - Same change as killjoy where you can only destroy trips by shooting them. Also his ult is bottom 3 weakest ults. Make it so that he can use it anytime anywhere instead of the whole dead body thing.
Sage - No changes. Balanced imo.
Chamber - Same change to his trip as stated for kj and cypher. Also fix the bug where chamber tp's away but still dies (if you tp'd away you shouldn't have died and if you died you shouldn't have tp'd away)
Deadlock - Reduce the HP for her wall. That shit busted. But also her other abilities need buffs but idk what. Help me out here.
Initiators
All initiators are mostly balanced rn imo which is also reflected by decent pickrate all across (except Gekko). So mostly no changes.
Gekko - Make it so that if wingman dies while planting, the spike returns back to Gekko (or the nearest teammate, if Gekko is dead).
Skye - No changes. But as a Skye main, I would love if they made her heal like sage's where you can heal a teammate for 100 HP or heal yourself for 30 HP.
Kayo - No changes. But fix the knife info bug.
Fade - No changes. Balanced rn.
Sova - No changes. Most balanced agent in the game.
Breach - No changes but slightly tweak how all stuns in the game work so that you don't get headshot by a full-stunned enemy so often.
Controllers
Brimstone - No major changes. Maybe give him his 2nd stim back
Astra - No changes
Viper - I think her smoke rechargeability is very broken. For example on a double controller setup you can just spam the viper smoke in alternation with another smoke to basically lockdown an entire section of the map forever. Look at how Split mid is played. Slow down her gas regeneration time slightly. And don't let her smoke orb decay enemies all the way down to 1 HP. Only her ult should have that feature. Smoke should bring you down to maybe 120 HP where you die to 3 vandal bullets instead of 4.
Omen - Reduce the cost of Paranoia with the sole intent of fixing his Pistol round buy. Other controllers get way better utility on pistols. Also his ult is so shit. Make it so that enemies can't tell if he cancels his ult midway (cancelling it now gives off a sound cue). Other good ults literally impact the entire round so Omen's ult should be able to confuse the enemies at the very least. That's bare minimum.
Harbor - I don't fucking know. Help me out here