We had better logistics and far more air power. The Russians had better armor and more of it. Also more men, and most important - the political will to throw them all into a meat grinder.
Now, something that *might* have been interesting was what some of the errant Nazis (read: Hitler's internal opponents) were proposing in the summer of '44. Namely a German alliance with the Allies to fight the Russians. German technology + allied logistics and air power = no more Soviet Union.