Doing Harry Potter again? only if it's animated, or when Radcliffe will be old enough to play Dumbledore. Lord of the Rings is 20 years old and no one is talking about a reboot, so the HP movies should better last for an entire generation.
And.....I'll get burned at the stake for this.....I personally wouldn't mind seeing (once Hamill, Ford are no longer living) a reboot of the OT to tie together all the afterthought Cannon that was shoehorned in. Not a shot for shot....line for line per say....but a cohesive story that includes all the added storyline that wasn't even thought of during the OT.
All things considered, it's not even such a horrible idea. Once you remove yourself from the immense attachment people have to this series, it's not that dissimilar to remaking an album once you have the budget for a proper production (and maybe some unfinished songs that were eventually completed). We could have proper coherent dialogue, have the Emperor with a more prominent role, remove the wacky Luke and Leila triangle, and give a sense of "yeah, we know what we're doing" that stands a full rewatch.
Then again, should they account for a reboot of the prequel trilogy as well?
how should they deal for example with the line "when I left you I was only the apprentice", when in reality it was Obi-Wan to leave him.... for dead.... to burn away with his limbs chopped off?