I have played a few 4v4 games as Soviet and I've changed my mind.
That thing is so fucking good. Especially with snipers, which help to take out PSchrekked PGrens and Paks.
Lowering damage won't help much, because 360 noscope long range AoE suppression will counter any infantry play anyway.
I think that locking upgrade behind T4 is the only option. Though I fear that it will repeat fate of Wehrmach Flamer Halftrack, despite it have no need to get into grenade range to shoot.
Personally, I'd better plant 4 mines in late game.
EDIT: I have to add that I never faced EARLY Pak. Opponents always tried to rush Puma/Panther or Ostwind/Pz.IV.
Luckely you've seen the problems now for yourself. So what we told wasn't utterly bullcrap. Point is that the early pak is just not flexible enough to take out a M5 since it can just flank you and take out your pak in only 2 seconds. Therefor a Puma does a way better job since it's armour is more resilliant against M5 Quad power