Ghost said:

Also, do you think it would work to put the Luke on Dagobah scenes at the beginning of the movie. It would make the whole Luke a master Jedi thing more believable.

I must respectfully disagree.

Come RotJ, the last time we saw Luke, he was licking his wounds, so to speak, on the medical frigate at the end of ESB. By starving the audience of Luke's appearance for so long in the begging of the movie and teasing them with dialogue about him spoken by other characters, you build anticipation. People will be wondering, "Oh, man where's Luke? I wanna see Luke? Why isn't Luke here?" It makes the sudden appearance of this wiser, stronger, more mature Luke Skywalker/Jedi Knight - who is nothing like the beaten and bruised teen from the end of ESB - all the more powerful.