Had the Germans employed diesel instead of gasoline engines.....and had they not had supply problems because of the latter......The advent of the Mk. V Panther (fast and powerful), the Tiger II (even more powerful) and the known power and agility of the Jagdpanther would have at the least elongated the war. Even the Jadgtiger made a play, but Carrius himself found it to be poorly designed, despite its high velocity gun.
I agree the SU-152 and the IS main battle tank were fearsome, but they didn’t change tank warfare like the Tiger I did. They were necessary evolutionary steps to keep pace. The US never really got there, so they went the quantity over quality route. A winning move given the circumstances.
Even though Jap tanks sucked big time they had great optical sights and diesel engines. WWII had many weird twists...