Assault have assault rifle buff
Support have LMG buff
Engineer have SMG buff
Recon only has Sniper Rifle buff which is useless for half of the training paths (there are only 2)
Spec Ops training path does not benefit from Sniper Rifle buff, but both training paths in the other classes can benefit from their weapon proficiencies.
Having Carbine or DMR proficiency is an option, but I like the other poster's idea better: suppressor proficiency. Either a minimap range reduction/removal, or no bullet tracers when using a suppressor. That sounds fun and thematic.
Since the footstep sounds were increased, on top of the nerf to the stealth tactics perk in the same patch, I have had people locate me via footsteps when while crouched or crouch running in quiet areas like a house in Eastwood. 😐
Instead of the mine or the anti-drone gun that was nerfed, I now use the Laser Designator as my second spec-ops gadget. It spots well like a drone and has thermal with zoom levels, and you can place it facing a flank to auto-spot anyone who enters (a bit like Valkyrie cameras in R6Siege). Painting is useful even if engineers don't make use of it, since it 3D tracks the vehicle so you can avoid it or plan your C4 run.
C4 is very hazardous to use. Because of the reinforced armour perk, I have to plant 4 on the vehicle to be sure of a kill. In this fast paced game, five seconds of planting and the slow trigger pull can only be done on clueless vehicles. In previous games only 2 sufficed, so I wouldn't mind seeing 3 destroy a vehicle no matter what perks it has.
Recon snipers should have aim punch when shot scoped-in.