Just a few nitpicks.
The Soviet medium and heavy tanks of the early cold were all around superior to anything the Allies or Axis had developed. The T-54 was unlike any medium tank in terms of frontal protection from KE weapons, and the IS-3 was frontally impenetrable to almost any WW2 weapon when it was deployed in late 1945.
However, once sabot rounds became reliable enough and fin-stabilized HEAT rounds made RHA armor obsolete, the Germans took those conditions into account when designing the Leopard 1 and Kanonenjadgpanzer. Very little armor, but high mobility and a gun that rendered the concept of the heavy tank useless. They were intended to ambush and conduct hit and run attacks in terrain where superior gun depression would limit exposure in hilly terrain.
Once composite armor allowed for the creation of modern day MBTs, the differences in design philosophy became more clear. The Soviets always placed crew as the lowest concern of tank design, and as such they were designed to function with little training, and height restrictions for crew members were needed in order to actually fit inside. They also use autoloaders extensively, as this removes a crewman from the tank, making them smaller still. NATO tanks kept the loaders, whose extra volume required a heavier tank for the same level of protection. The extra training crews receive can allow for more complex maneuvers, even against superior numbers or against a single tank of more advanced design.
