I think i can see what andreas is trying to say (i may be wrong) but this is a reward unit for an assault gun/self propelled artillery unit its not meant to be a tank killer and im not sure why you would want yet another dedicated heavy tank killer when you have the elephant and others to fill that role.
I am just saying that it doesn't make sense to include it, if it is going to be tuned Down to the level of the KV-2 or AVRE. Then it would make much more sense to include just the Brummbär.
It would be like including a Railway gun,l and tune it down to a hummel. I know it's not entirely realistic, but it just doesn't make sense..
It would be like including a Tiger/King tiger and tune it down to a Panzer IV...
If they included the IS-2 with the stats of a T34 - that would just be silly.
You get the point. Either it will be very expensive, and be a monster. Or else it will just be a joke.