Wasn't it our Gen. Patton who wanted to move across the River £aba and finish the job by rolling back the Soviets...preferably to beyond the Urals? Then Poland could have recovered her pre-partition territory and add some extra land as compensation collaboration with the third Reich, Katyń, Siberia, Kazakhstan and other Russian atrocities.
As much as idea of not having fifty years of communism here sounds fantastic, I think you don't fully comprehend the fact, that you parallel history would mean that Poland would have become a battleground of WWII for the third time, at least. After that there wouldn't have been much left here to even name the country. Poland would have been an empty shell after that... Now, at least we have Cracov untouched. If we add to that atomic bomb which was invented around that time...
Anyway considering circumstances current borders are quite ok, and I wouldn't mind to stay it that way to the end of time ;)