Other than not having the "Romance of the Three Kingdoms" and its effect on Chinese culture, would this have made a difference?
Cao Cao did unify most of China. The southern territories occupied by Wu and Liu Han at the time were much less developed and much less Chinese than they later became. Later on, his successors were overthrown by the Sima family, who had no problem conquering the southern kingdoms and starting the Jin dynasty. Presumably, if Cao Cao founds a new dynasty, its overthrown anyway by the Sima when his successors don't measure up.
There are a number of occasions in Chinese history when one dynasty conquers all of China, only to not be able to consolidate and get replaced by some other dynasty a few decades later.