OK, here goes.....
Vader could not have destroyed Luke,
Vader COULD have destroyed the emperor, the emperor just trained Vader to Fear him and think he was more powerful.
Yoda AND/Or Obi-Wan could have easily defeated Vader and/or the Emperor, they just knew the only way to turn Anakin back to the Lightside was throught his son.
Luke would rip the beard of off Katarn.
It was stated that Katarn destroyed seven Dark Jedi, in all the books and all the comics, how many did Luke destroy... and how many times did he save the galaxy, how many times did Katarn, but anyways, why would they fight? They wouldn't. They'd be happy little Yavin 4 forest Fairires and trade nice "happy"
stories of Jan and Mara.... *sigh* to be a Jedi (Knight(II))