The problem with comparing it to the IS 2 and saying its fine is that the IS 2 is also in a pretty bad spot right now. They both have the same problem, their scatter sucks, so they can hardly hit infantry, the difference is that the KT has to fight larger and better squads with better supporting TDs.
That's why KT has more hp and higher damage.
It itself also is supposed to have a backup of infantry.
And I completely fail to see how a tank having to fight tank destroyers which hardcounter it should be any issue here. If you are using all or nothing card, you need to be ready to lose it when opponent is prepared with correct counter, especially now that allied TDs are actually able to put a dent in its armor.