Just my two cents:
Are you familiar with StarCraft? The KV-2 is basically the CoH2 version of the Siege Tank from that game (gets a big refire rate and range increase with a toggled ability that sacrifices mobility). In my experience, it actually works best as mobile heavy artillery. But to use it at its full potential, you MUST use its deployed "turret mode". It has roughly the destructive power of the B-4 (thanks to much higher fire rate) but is way more accurate and will auto-attack any targets in range like a mortar. Thanks to its impressive range when in turret mode, it is particularly effective at helping to deny capture over multiple sectors if you position it well.
Is it strictly better than the ISU-152? I will never say that, but you have to look at costs and trade offs too. For starters, the ISU-152 is more expensive in every way (MP,Fuel,pop). You also have to account for the other Commander abilities that are included with these vehicles. Ultimately, it depends on what you are looking for. If you just want a better TD, the ISU-152 is the obvious choice. But if you want some heavy indirect fire support with more consistent fire rate, the KV-2 is the better of the two for that. Either way, the weaknesses of either can be supplemented by other units in your arsenal.
Functionally, the KV-2 does exactly what it was always suppose to (it was built to be a bunker buster). If you want to talk "balance" maybe adjust unit cost as needed (I don't have any strong opinion about that), but that should be it.
Of course, some opinions here may differ, but from what I can tell, I don't think most people use it as it was intended; if you treat it like heavy artillery, it does great.
You are right in that ISU is slightly more expensive but not by much. I feel like the KV-2 does not perform well for its cost.
I am an avid Starcraft Broodwar and Starcraft 2 player. I like how you compare the KV-2 to the Siege tank since both have the siege tank. The Starcraft 2 siege tank has instant undodgeable splash damage while in siege mode and it has a different weapon in unsieged mode. I have said this before but the KV-2's projectile is incredibly slow and can be easily dodged especially at range which makes it ineffective against anything that isn't standing still. In addition, there are no 'bounces' or scatter in Starcraft. The siege tank is reliable, accurate high burst splash damage. The KV-2 is very unreliable in penetrating armour and hitting infantry especially at range because of its slow projectile speed.
I want to bring back the cost into account. The ISU is only slightly more expensive but it has fast moving HE shells for wiping infantry that cannot be easily dodged unless by scatter. It comes with AP rounds for engaging tanks and it has the range without entering siege mode.
IMO. As a late-game doctrinal tank, the KV-2 probably ranks as one of the worse late-game doctrinal tanks. In that it must expose itself unnecessarily and it is mostly ineffective for its cost. I think the KV-2 was good when it was released by the evolving meta/changes of Coh2 has forgotten our humble KV-2.
Edit: I don't like being an armchair developer complaining about something and not proposing changes so I think the following should be put into consideration to bring it more in line with other heavies.
- Cost needs to be adjusted if no other buffs are made
- Projectile speed needs to be looked at. Either changed to a fast projectile like the ISU or increased travel time like the comparable to the Brumbar which this tank competes with.
- Siege time needs to be shortened. See below.
I think the comparison to the Starcraft siege tank is a very good one. The Starcraft siege tank has a clear and defined role. It is powerful but it has it weaknesses too. I think the KV-2 should move more into a siege tank type role in that it is less effective while unsieged but more effective while sieged.
Setup siege time should be around 3-4 seconds while unsiege should be slightly faster at 2-3s. Currently I think it is around ~10s(?) which is far too long and makes it far too vulnerable to artillery or call-ins. There is no counter play with anything more than 3s of setup/tear down time.
These are preliminary changes with future changes to adjust reload time, penetration and AoE based on performance.