Panther's armour with some other means of AT have very big potential to fully destroy the IS-2, that's what i meant. I understand your point of view, but the changes I suggested to the IS-2 would also increase it's cost, and by that I also mean popcap. It would still be a worthy trade to defeat the soviet superheavy.
Lower rof and higher damage for the IS-2 would also mean that it's micro potential would be higher, as you could reverse after every shot, but it would preform not so well while fighting straight face to face. I don't want the IS-2 to wreck everything, I just think that it should be an investment having impact on the game, while also feeling unique, and not falling into the category of "welp i guess my commander has it so i might just as well try to use it".
Do you mean with higher damage that it should be buffed in AT, AI or both?
I mean, I see your point as well. However I am not sure if your design idea would work. The IS2 is currently a brawler, meant to stand in the middle of the fight. You can't pop in and out with it, it is just not quick enough to do so, neither has it the range to make it viable.
Giving it it even lower ROF while retaining the generalist status would mean it must deal more AoE damage vs infantry as well. It's AoE stats are already decent, and AoE damage is tricky to get right vs Axis squads to not wipe them out too quickly. However it might probably be doable.
Then again, ROF is probably more important vs armored targets than some slightly higher damage increment. Lowering this would make the IS2 very vulnerable if it misses the first shot.
To sum it up:
Lowering the ROF even further would mean increasing the wipe potential while decreasing reliability. 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 doubt that those changes would really make the IS2 special, it would probably just push it even further into a niche corner.