I find the is2 pritty good, but its not op at all. Its funny that a 600mp /130f medium tank can i give a 760mp/240f HEAVEY tank a run for its money. if any thing it should be; panther are you kiding me !!!!!!
First off, the IS-2 is basically a Sturmpanzer and Panther in one. The combined cost of a Sturmpanzer and Panther is 1280MP / 270FU. Sure you can buy one while you wait for the other, but it's still a steep cost.
The IS-2's main gun has higher damage and a large blast radius than the Sturmpanzer IV. For specifics, the instant-kill radius is 2.25 (IS-2) to 2 (Sturmpanzer). That's the the strongest AI Tank on the Ostheer side, being beat by an AI / AT Tank at it's
only job. Keep in mind this is against 4 man squads rather than 6, so even if they were statistically identical, it'd be better by proxy.
Now we have the Panther. The Panther shoots faster than the IS-2 does, and both have the same penetration. But the IS-2 has higher armour and higher damage, enough to make up for the ROF difference. Assuming they all penetrate, the Panther will kill the IS-2 in 6 shots, and the IS-2 will kill the Panther in 4. Those 4 come out slightly faster than the Panther's 6. The Panther's 7th and IS-2's 5th shots are roughly the same time again. The Panther has a 52% chance to penetrate the IS-2 from the front, the IS-2 has a 63% chance to penetrate the Panther from the front. Not a lot of difference, but at the same time there is. IS-2 comes out on top here.