Can't watch the teaser yet, but lookin forward to that when I get home.
Honestly, Empire is a near perfect film in my opinion (even the SE now that Luke's bizarre 1997 scream is gone) and besides colour correction, I can't think of anything that really needs changing.
However, anything you add I'm sure I will be pleasantly surprised to see.
More walkers/speeders in the Hoth battle and more TIEs in the Falcon chase would add to tension I suppose.
Boba's voice was fine in either version I thought, won't bother me either way.
The Emperor's new hologram I agree could use some work. I don't think it's that bad, but I'm really interested to see how you tackle that.
And I'm sure there are little technical issues and crap that could use tidying up.
Good luck with this!