high damage IS-2 has been tested:
IS-2
Heavy armor saw an increase in performance to better highlight its tech placement. When a player transitions from light to medium armor, there is a very clear differentiation in the power of medium vehicles vs. light. This change better highlights the transition from medium to heavy while still retaining the role of medium vehicles in the late game. Lower rear armor maintains the value of flanking while increased combat potential better addresses the tech level of the vehicle. The IS-2’s anti-infantry capabilities have been reduced and compensated with increased anti-armor.
Armor from 325 to 340
Rear armor from 225 to 205
Penetration from 170 to 220
Damage from 240 to 160
Reload from 9 to 6.2-6.6
Distance scatter max from 2.86 to 5.7
Manpower from 760 to 640
Fuel from 240 to 230
Its pen played a bigger role than anything in making the low ROF unsustainable.
It was an odd duck back then, able to nuke infantry every 10 seconds but could lose a duel with a p4 due to its pen. If I recall that was before range dependant pen as well eh? (damn this game has come a long way) so it could be tried again and better tuned now that it's aoe has been made more balanced and heavies are not unlimited and now tied to tech.
Not sure its necessary at all to do so but the game has changed so much since then that it didn't work then doesn't mean it wont work now.