If it's limited to only balanced then:

-SMGs will see a nerf, likely.
-Maybe a nerf to certain attachments in general. Guns get way too laserbeam-like once you get them leveled to a certain point. Makes it very frustrating start playing or to try a new gun.
-Removal of C4 from being available on literally every class. It's not required. Or at least to reduce the amount you have.
-Buff transport gunner accuracy/damage a little.
-Buff tank F3 gunner slightly with either accuracy or damage.
-Make Humvee/Tiger's windows bullet proof. Theres no reason why you can be shot through them when there's clearly such a ubiquity of AT capability running around.
-DMRs. I've just unlocked the EBR and it's absolutely incredible. Which is in stark contrast to the M110 and Mk20, which are uNpLaYaBlE. Increased velocity I think would make these so much more satisfying.
-An incentive to play Frontlines would be cool, like a 2xp (as well as clearly marking it as such). A similar carrot for any underplayedap/mode/time of day.

If if they want to sneak some other QOL stuff in:

-Minimap. Holy moly, please a minimap.
-Flag status at top of screen. For some reason it's only on Frontlines as a feature, but no other fame mode. Perhaps they just haven't gotten around to it yet.
-Add more depth to the audio. Although I think this is probably way beyond the scope of this patch.
As a Tarkov and Squad player I'm probably spoiled by what good quality audio is (quality not implemtation, before you try and tell me Tarkov's audio is terrible). -Stop locking squads on map change! Holy heck.
-Better contrast for in vehicle ammo status. Most are small and difficult to find due to lack of contrast. And some just don't even tell you.
-And on the same vein as above, add a vehicle health indicator. PLEASE!
-Hit reg can be atrocious sometimes. I'm sure it's an ongoing battle with the Devs though, so let's just see how that goes.

I'm sure there's more, but that's it off the top of my head. Otherwise I am having a great time.