The OP basically answered his own question, in the affirmative. Plus, as Locutus
correctly points out, no Lando, no beer, no Rebel victory. However, there are other things that would have turned out differently, had Luke not disobeyed Yoda.
By the outcome of his duel with Vader on Bespin, Luke observed and realized that Vader wasn't trying to kill Luke, but rather that he was trying to turn Luke, in order to
avoid having to destroy him. Empathizing with Vader, understanding his motivation, and realizing that by caring for Luke there was still good in him, gave Luke the key to ultimate victory over the Emperor: turning Vader back to the good side.
Further, if Luke hadn't gotten his hand sliced off, and gotten his artificial hand, he wouldn't have been able to empathize with Vader on the visceral level that he did when he observed Vader's cybernetics after the duel on the DSII. This was a big factor in keeping Luke from falling to the dark side.