Okay, time to actually write down a post to post my opinion on how I'd balance the guns.
First off, a overall improvement on the netcode and overall less RNG on all guns, that's what I'd like to see, then:
Scout - bring jumpshooting back, i literally don't see a reason for it not being back, it made the gun fun to play and it was so easy to counter. And the animation delay that happens after you shoot a shot with it (though thats due to sprintshooting not being a thing anymore). OBIR has the same issue as well. Remove them for the guns to be more dynamic.
HVR & variants - lowering damage to 720/725/750 (whatever works out best)
COBR-A - reverting back the changes when to when it got 'ninja' buffed, that was the most fun COBR-A.
Shotguns - actually make them less RNG, I swear the JG is unusable sometimes. Overall they're fine.
Scoped NTEC & URSUS - Revert them back to their old state, before the huge 'ntec nerf'
Tommy Gun - I remember it being better before they nerfed it, get it back to that state.
STAR LCR - same story as with the tommy gun, unsure on this one.
STAR & variants - IIRC, this gun never got any changes to it, I'd like to see it getting a bit of a accuracy buff
OCA - Get it back to the state before it got buffed (the one that made it "op") so less people cry about it. (This one is a big ??? for me personally, as I don't find the OCA that broken)
VAS C2 - now this is a tricky one, I'd like to see it be on par with the ATAC honestly, but without being the sniper it was back in the days.
Now, I can't vouch for the new guns that got recently released cause I've barely tried them/have never tried them (Norsemen guns, S1 series etc.)
oh, and I'd love to see a higher TTK (longer time to kill) and sprintshooting back (makes the game more dynamic and fun), but we'll probably never see this due to the developers not wanting to improve the netcode and animations.