Maybe, I would think rather than going 8k, (it was 4K in Imax I believe) that he would do very high frame rate - say 120 fps.
Going to see the movie was an experience. And unlike some of the suggestions here, No 3D wasn't 'New.' 3D had been around a long time. Even Alfred Hitchcock made a 3D movie!
See: http://www.amazon.com/Dial-M-Murder-Blu-ray-3D/dp/B008ERNLTS
What was different with Avatar's 3D was that it was Really, Really good 3D.
The big innovation was completely rendered 3D worlds and characters. We realistic facial expressions and movements that were on the other side of the uncanny valley. I walked out going 'how did they do that?'
I know people like to say, 'It's just like xx story,' but they end up going through 15 different stories - which mean it isn't exactly any one of them, but a mix of all of them and told in a different way. Even William Shakespeare ripped off all sorts of legends and stories, but he interpreted them and told them in a new and different way.
Maybe, it just depends on how it's done. Avatar was real 'go to the movies' experience. A re-issue would have to offer something that people can't get at home. And with 8K TV probably being fairly normal by then, it may be a challenge.