Panther did way better, so did king tiger, and the tiger I
Oh really? I pretty much doubt it. The panther is indeed a great tank but it had several problems:
1) Fielded too early cutting the effective force in half because of mechanical failures
2) By the later stages of the war, the quality of German's armor composit was severely reduced by the lack of different alloys in the german industry.
This meant that even though the IS-2 had problems with a low quality armor piercing round, the sheer kinetic energy of the 122mm shell would crack the frontal plate.
3) The tiger and king tiger were complete and utter failures from economic and macro point of view. Their cost was unreasonably high, had a very hard time being recovered, often required a complete removal from combat for repair. The weight restricted it from many bridges and crossings. Designed as a heavy tank for spearheading major offensives,
it ended up being shoved to shut armor dangerous areas, time to time being rushed on trains because of the sheer weight and mobility problems.
4) the king tiger had so many suspension problems that it was not much more than a mobile pillbox.
5) the IS-2 wasn't designed to combat armor but to destroy heavy fortifications, hence why the d25-t 122mm gun was taken over the ds-10 100mm gun which had unitary rounds, and a better armor penetration than both the Tiger 1 and Panther armament.
P.S All hail the :IS2: