Soviet guard are elite infantry that come equip with PTRS At 2 CP.The problem is PTRS only useful in the early game.Which is around 5-10 min(Time between 2 cp to medium tank).Then The power of PTRS significantly drop after that to the point that it seem insignificant.
Guard's ability to slow the tank have limited range.The player who Know the game know that he can just snipe them from max range outside PTRS range and even if he move his tank to ability range he still need to be super close to them to make it worth ammunition cost.If You try to use this ability when enemy tank is at the edge of the ability range can will only get slow for 1-2 second before he can move outside the range.
Also one of the main problem is the ability can be counter by smoke which if I remeber correctly cost cheaper.
The main enemy that Guard will likely face at their "timing" are
1 okw flack truck
2 panzer 2
4 222 scout car
As you can see 2 of them get smoke as base skill and 222 can get smoke from commander ability.
During the late game the enemy just make sure that he stay out side guard's ability range because the ptrs damage is super low.
The ability meant to discourage enemy tank from rushing in but losing half of the tank health from panzershreck is also discouraging too.Also con AT nade also better in some way such as it require only 1 model use the skill while other can keep shoooting something else.While guard's ability require all model to shoot at the tank include the one with DP-28 thus reduce anti infantry damage significantly.Con at nade is parmanent thus they can use "hit and run" tactic.While guard need to stand there to apply debuff thus put them self in even more danger.
My perposal are
1 reduce the cost of guard ability to 20 because the ability is rarely get use and can be counter by smoke most of the time.
2 Add upgrade call "advance anti tank rifle training" to guard.It will cost 40.
The ability are everytime guard's PTRS hit enemy armor it will have chace to inflect some debuff to enemy tank.Maybe temporary engine damage -20% speed for 5-10 seconds.The propability will increase after frist volly and stay at the cap after second volly.
The ability will also get stronger when the guard get some vet.
Frist volly have 2% chance for each shot.It will increase to 3% after frist volly and we will use that 3% as cap.
Vet 1 frist volly 3% for each shot after that 5% for each shot
Vet 2 frist volly 4% for each shot after that 6% for each shot
Vet 3 frist volly 5% for each shot after that 8% for each shot
If the tank did not get hit for 30 second the add up chance go back to frist volly chance.This is some what Similar to AEC shoot the track skill.
This upgrade won't turn guard to tank murder squad Like pgrenshreck.But will turn it too infantry squad that capable of open up opputunity for other squad to exploit and can not be ignor enemy in the late game.