having more than one shot will simply make the weapon completely OP against infantry. As things stand with my skill level I can 2 shot almost any suit. The 1 shot is there to keep the weapon balanced.

Fix the reload animation so as not to block my view of the impact on all but the longest shots. Let me throw a nade while the shot is in the air, and perhaps a better reticule and some feedback telling me I actually hit the target.

I know this has been suggested before but I don't see any of you mentioning it, as I recall CCP liked the idea too.

Burn damage.

Keep the current damage, then on a direct hit the weapon dealing that damage again over 5 seconds. Then while aiming down sights you get a trajectory arc and it actually becomes modestly useful at ranges other than touching distance.
It is very effective vs shield tanks as the burn damage prevents them from passively recharging and is modest vs armor tanks who can rep through it anyway. It is limited by it's single shot clip, limited ammo pool, travel time, and trajectory arc.

CCP is taking burn damage into consideration but CCP does not know how to fix the PLC without making it OP vs infantry.

It isn't OP vs infantry now and by making the only change the adding burn damage only to direct hits it's effectiveness as an AV weapon increases drastically. A direct hit will almost always kill infantry anyway, regardless of burn damage. Although I do admit it would be amusing if it left a "burn zone" on the ground that deals damage to anyone who walks over hit (but only as much and for as long as it would normally deal to a vehicle). So it would then gain modest area denial abilities.