It implies ISU-152 AT performance is bad which is not.
Compare to what and against what?
It takes more time for ISU to kill P4 then for SU-76.
Against late game armor above P4, its AT performance is bad, supplemental at best and incomparably lower then SU-85 which costs half.
On the other hand its AI performance is OP but that does not mean that it AT performance is bad.
If you say that about a unit with largest scatter and longest reload in game, I'd like to know your opinion about Brummbar. By that metric, we probably should completely redesign or remove brummbar from the game for how OP it is, wiping all squads in 1-2 shots with 100% accuracy.
With long range, high penetration, deflection damage and powerful AT shot ISU-152 has great AT even if its AI performance is even better.
Is this why despite ISU being used often in team games, literally no one uses it for AT ever regardless of opponents armor composition?
Also, no one in his right mind will use 90 muni to deal 240 dmg to a vehicle with a skill shot.
Play the game sometimes and use the units you try to argue, in your excel sheet every unit is OP, reality strikes a different image.
The unit should be used for AI when there are soft targets and AT when there are hard targets.
That's opinion, not a fact.
Its supplemental AT at best because of reasons above.