The problem with the IS2 is its Armour is excessive when comparing it to a Tiger. I have had 2 games recently where it bounced almost 75% of shots from packs, stugs and P4. In one game the sov player just parked his IS2 on the vp and did not move it while I had 2 stugs and pak all firing at it. The first 3 volleys from the stugs all bounced ( that 6 shots ) and 2 shots from pak bounced or missed.
I am not an expert at judging distance in the game, so I would say they were at medium range because no infantry was in front to spot for them and they were stationary the entire time. I don't think getting closer should be required because I am then putting my tanks at massive risk to satchels and snares, not to mention the stug often has terrible pathing and cannot get away. As to the idea of flanking, well that is just a massive waste of time as the P4 also bounces almost all the time and if you keep moving then you will often miss even at point blank range.
As to getting a panther, that often ends with a dead panther because the panther will bounce or miss with higher than expected regularity. If the soviet player pairs a couple of Zis with the IS2 then it becomes even more difficult and almost suicide if Rng goes slightly against you. To make it worse if Shocks attack and clear opposing At guns or if offmap is dropped then the axis player is at an extreme disadvantage despite having similar units and having spent similar fuel etc.
It is significantly harder to kill an IS2 than it is to kill a Tiger even though the cost is similar.
I do understand in team games it is probably no huge issue because focus fire can force it off but in 1v1, I find it enormously hard to kill if it is supported properly and I find it hugely frustrating watching it bounce so many shots. I will say that I have killed this unit on a number of occasions by overwhelming it with multiple stugs and paks but on most occasions it is because the sov player overextended.
I have no real issue with its damage output but its survivability needs to be inline with the tiger.
