http://www.youtube.com/watch?v=ZAfOrr31FIw&feature=youtu.be
Here is a very (very) rough mock up of what I was suggesting for an opening Dagobah scene. I removed the sound altogether as it was all over the place and it would take much more than a mock up to fix that so initiallyI'm afraid we'll have to make do with some annotations to accompany it, so here goes.
To start with there would be a new establishing shot showing the Xwing on Dagobah, then inside Yoda's house we would see him moving over to obtain his lightsaber crystal, talking to Luke about how the lightsaber is only a tool through which to use the force (or anything that sounds wise).
Then show him turning and moving the crystal which then falls into Luke's hand. Then we would pick back up to Luke and Yoda outside where Luke builds the Lightsaber using the force (which was inspired by this video http://www.youtube.com/watch?v=c0uqWOxsSx4 ).
Then instead of having Luke immediately ignite the blade I would have him walk off, and then we cut to the Yoda death scene shortly after. Then once Yoda dies Luke tweaks the lightsaber and ignites it (the deleted scene footage changed to set on Dagobah as shown in the photo I linked to earlier). After this Luke would move to his Xwing to depart and hear Yoda's voice urge him to hurry to his friends' rescue (as I described briefly in my earlier post).
I know this would reuse a lot of footage but given the limited movement from both Yoda and Luke, and the fact Luke's face is offscreen any time he would need to talk then Luke's speech shouldn't be a problem, and Yoda's is only limited really by his lack of existing lines, but I'm still playing around there, and there might be more sources I don't know about. But visually the backgrounds could be changed without much work, as there is very little movement, and even Luke's costume could be changed to a partly new costume, even if it would be difficult to make it match exactly with his RotJ one. I know it wouldn't be easy, but I do think it would be possible.
I think the benefits are it potentially has an awesomeness factor because it would be cool to see Luke build a lightsaber. It would also explain how he happened upon the necessary pieces to build one (because Yoda handed his old lightsaber down to a new apprentice). And it would increase the running time, which allows more freedom with other cutting without damaging the overall length.
The additional clips were to show Luke holding the crystal, and Luke examining the hilt after piecing it together.
Anyway I hope someone else might agree that this idea has potential (despite an extremely rough demonstration as to its execution).