The pakhowi already doesn't OS any full life squad so your first paragraph is out of subject, what you're proposing then isn't going to make its detractors happiest since it will be subject to kill more wounded models per shot. Low health squads are going to suffer much more from your change.
Then don't hang low health squads around while shells are landing nearby? "My change" is exactly what happened to ISU152 , 120mm mortar, brumbarr, and several other powerful AOE weapons
Also as I just pointed out the HEAT barrage is very capable of killing things. It does 80+ damage in just under a 2.5 radius or so
Idk why you keep saying it's barrage needs to be good. They are good. You have 3 types to choose from, all of which are useful