I'm aware that it's late to post new ideas (evreybody has ideas but no one works to accomplish them) and that it's late in the progress of the mod to implement them if they are actually any good.
I know you guys take into account very seriously ww2 realism and the balance of game play when making units and changes to RWM.
There are some redundent units when it comes to balance, the beautiful Jagdtiger is totally missing in most popular maps, because it's hard to balance and loosing such a powerful tank hunter hurts, but very few of them were built so it's kind of ok if refering to historical context.
Speaking about historical context the IS1 comes to mind, an abundant unit in multiplayer maps although only about 100 were built and some of them converted to use IS2 turrent. About the balance of these 2 units, IS1 is mostly balanced against Tiger 1 and i said there always in great number on the RWM multiplayer fronts

while the IS2 with some 4000 units built were until recently balanced only versus Tiger 2 and Elefant. Recently thanks to a few maps the JS2s are balanced against a combination of Jagdpanther plus other tanks (St Lo and Ukraine map), still only a maximum of 3 per player are used in the balance of the maps.
Looking into the realism of WW2 tanks i have to say that the IS2s where build in 2 variants:
1943 IS2 featured a stepped front hull design, similar to the KV design (sorry i didn't have time to search for a ww2 pic)
1944 IS2 featured a single angled front hull design that offered better protection thant the 43 variant, a new barrel breach which resulted in a bit faster rate of fire and an improved engine with a bit more horsepower and new optics
These are know facts and not obscure information, but if there are doubts about their validity i can give you a lot of sources of information about the subject.
Returning to the game balance issue, i propose a new variant of IS2, with the armor equivelent of the current IS1 but having the gun of the current IS2 with a smaller rate of fire and with a slower turning rate than the current IS2.
The up-gunning of the soviet most used heavy tank in RWM (IS1) will make a considerable impact on gameplay and balance. As for game play the new unit may promt the need for the use of Jagdtiger tank destroyers.
Balancing is a different issue, the new unit would have a reasonable balance if used as IS2 1943 + SU85 vs Nashorn + Tiger 1 / 2 Panther + Nashorn (German advantage) , anyway there are alot of balance combinations that work.
My idea is to eliminate the IS1 tank as the main heavy tank of USSR, totally not real!
IS1 106 units (if i remember correctly) with most of them being rearmed as IS122
IS2 (1943 + 1944 variants) nearly 4000 units made by the end of the war --- Wiki says 3854, doesn't matter, even 2000 is enormous compared to 100.
It's good to come up with ideas and do nothing and wait for others to implement them, i'm not a Sudden Strike 2 modder but i could be if you need me, give me the tools and point me in the right direction if you ever need help with something.