Nah. No where near the impact as the Su-100 or KV-1. I'll have to dig into my sources, but iirc the JS-2 tank had a rate of fire that would make the King Tiger feel like Speedy Gonzolas. The JS-2 tank's 122mm had 2 piece ammunition, the projectile and the propellant were loaded separately by the same crew member. I think there was a max rate of fire of 2-3 rounds a minute (20-30 seconds to reload the main gun!!!). The 122 main gun could penetrate 115mm of armor at 1000, which was almost identical to the Panther's 75mm and Tiger's 88mm, but still inferior to the King Tiger's 88mm cannon's 165mm AP ability. The JS-2 has 120mm of sloped armor on the front, so it was well protected but it was not immune to late war German tank fire. A powerful tank in its own right, but if HTC decides to add another Soviet tank any time soon I think they should add the Su-100. It saw far more action and was far more prevalent on the Ost Front compared to the IS-2.
My 2 cents.
EDIT: I looked up some tid-bits on the JS-2: best speed was 23mph; max ammo load for the main gun was 28 rounds (yes, 28 rounds); its HE round was considered its main asset.