Good job.
It's a shame that you can't tinker with them in a 'clutched' position, so it looks like they are struggling back and forth at a moment, almost at an empass.
I would add in some more dialogue from Vader or some off screen stuff from Ben. Possibly a Vader "You don't know the Power of the Dark Side" right after Obi Wan smiles and right before Vader strikes him. Re-using some frames, or just playing them back again...it would allow for the score to sync up alittle bit more or finish and would also look back towards "You underestimate my powers".
I'd also add some more saber clashes while Luke is running out, so it doesn't look like off screen they are just standing there. You kinda need to link the two images together, since you've not cut them out of place. The Saber clashes would be a small step, at the worst, you could rotoscope that (blah) to include the same background behind Ben from the opening area he is fighting in.