I do not know about Yugoslavia but it is certain that the Ceausescu regime would have ended up in misery either way. Having as a ruler an idiot who is capable of playing opponents against each other and who was enthralled by the prospect of having a personality cult ensures things will never end well for the people.
I would argue that China and Viet Nam aren't good examples either.
The issue came in because the US wanted to break up the soviet bloc so the World Bank went to town and made sure that happened.
We will never know what would have happened if Tito and Ceausescu would not have been squeezed by debt and foreign interference.
Maybe the reason you don't see a good example of Communism besides maybe China/Viet Nam is because the west is actively engaged in making sure that doesn't happen.