Players though use to prefer a reliable unit over an RNG one (hence why Panthers I are preferred by most instead of StuGs, despite those having similar to better DPS per population/cost - health etc aside).
I disagree, the reason the panther was used was sheer survivability. You could lose a StuG III twice before you'd lose a Panther in the same situation (70% more health and 90% more armor plus turbo switch). People used the Panther because it could either be sat on the frontlines or used to bullrush the enemy with little fear of it being easily destroyed. Consistency certainly isn't the main concern because the Panther's inability to hit targets consistently was long considered it's main detractor alongside cost, until the recent patch buffed it.
About the IS-2, the wipe potential could be reduced by limiting the number of models it can damage per-shot. For some reason the developers rarely use this feature even though they used it on, of all things, the bloody 45mm gun on the T-70. I just think the IS-2 would fair better if it were to at least gain 200 damage, but 240 would be preferable. Lowering the rate of fire is not preferable because when it was slow, it often had the problem of shooting at the wrong target and having to wait, and misses with the gun were more painful.
Then again, given the choice between the old IS-2 with the slow firing 240 damage gun, and the new IS-2 which was redesigned to not delete Grenadier squads every 8 seconds, I'd take the old one every time. It was useful, the only use of the current IS-2 is that it's not crap like the T-34 and can stand up to most German tanks, even though it's German contemporaries can kill it.