Mediums are not very effective in this game because the engine does not model side armor.
In my opinion they're less effective than they should be because of engine snares. Snare abilities are either too common or too powerful (talking only about infantry snares, not mines) It's crazy to think they use to kill the engine on full health tanks
____________
I don't think a moving accuracy buff at vet 2 or 3 would be too crazy. Especially since mediums recently got a target reduction
Anything more than that though is unnecessary imo. Panther doesn't really need buffs