KV-1 is pretty weak, I would give it UT at best in the scale of this thread. Yeah, it has high rear armour, but without it, it would be completely useless. So there is that. Even now there is little point of building it. The only reason why it sees any action is becouse it has been put in one commander with newly overbuffed IL-2.
KV-1 is actually pretty solid tank at the moment.
Hardly overpowered in any way, but it now finally has a distinct job it actually performs good at.
With recent change, it really is in a good spot and since its both, doctrinal and in not breath taking doctrines, it doesn't really have any potential to be too good as long as you get a singular PaK and Panther, which will deal with them very efficiently, but meds alone finally can't walk over it.
KV-2 doesn't need rework as a singular unit. The whole commander needs it. As it stands now, KV-2 is not worth its price for how late it comes and how easy it is to counter. Would give it UP in the scale.
KV-2 is pretty UP.
Its direct mode is terrible and its unable to engage anything better then P4, even singular StuG will massively punish it in regular slugfest.
Its arty mode isn't that great either with range making you expose it, setup and de setup times and horrible accuracy, but for whatever reason "people" still want to nerf it, one of the most underused and avoided tank in game...
ISU-152 is not in the same class of units as jagd and ele any more. Sure, when supported it can be worth its price, though only on the most favourable maps (that are also unfavourable 95% of other soviet units) It definitely doesn't need any nerfs to its armour, especially taking into consideration how quickly it dies when attacked from the front by TDs.
ISU is really fine as well.
For its tier, axis actually DOES have units to engage it.
JT and Ele got rear armor nerfs, because they are literally almost impenetrable frontally, while single Panther can be enough to kill ISU.