This “surprise announcement” (very vague) will either be the unaltered versions hitting blu-ray at long last or have nothing at all to do with a re-release of the movies.
But, as i have said before, there has been nothing even mentioned about a “surprise announcement” happening at Celebration. It’s just something that has been twisted from the official announcement of the panel.
The only two official things said about the 40th panel that mentions anything about “surprises” :
Official Star Wars site:
…this marquee Celebration event will undoubtedly include many not-to-be-missed surprises.Andi Gutierrez on the Star Wars Show:
Celebration is the place for surprises, make sure you attend this event. That’s all we are going to say.NOTHING about any announcement being one of the “surprises”.
Then forget the “announcement” part. Maybe that was just me making a freudian slip. But my original point still stands. If whatever the “surprises” are have nothing to do with the OOT, they won’t have anything to do with the SE either.
One of the conventions - it was either 2010 or 2011 - had a panel about the then yet to be released blu-ray where they showed off the deleted scene from RotJ of Luke building his lightsaber. It got a fairly big reaction from the crowd if I remember the camera phone footage correctly.
I could see them closing the panel with a sizzle-reel trailer on a 4k projector prominently featuring shots/moments from the unaltered version that were the most notoriously changed for the SE (Han shooting first, Mos Eisley, Battle of Yavin, Lapti Nek, etc), complete with the “original” color-timing, or at least as close as anyone can tell. Hell, even if they said it’s a work in progress and it’s not hitting until next year, seeing restored footage from high quality elements could still be a big crowd-pleaser.