Nice one. Leia, Chewie, Lando and Threepio captured by Vader. Falcon scrapped. Han taken to Jabba. Luke would be on his own to try and rescue Han, if he even ever found out. He'd either get tempted by Vader to attempt a save of his friends alone/with the help of rebel commando npcs or lead the space assault on the Death Star II and probably die since there wouldn't be anyone to convince the Ewoks to help take down the shields.
"Luke, know you now why never split the party you should. TPK, you noob. Total Party Kill." -Yoda