What a bunch of idiots. Yes the original looks extremely dated but it actually makes sense with the story why it would look so different. The whole point of that film is that real humans end up in a computer. Computers in the 80's were alot more basic than today and so it makes sense plotwise that the the two films would look very different from each other. When you watch Tron and then Tron: Leagacy it will make sense because in reality, computers have progressed alot in that time so it makes sense in the movie that the Tron world will have progressed as well.
Disney dont need to keep the film from people because they fear they will be put off. Thats insane. Were people put off by the Star Wars prequels because the originals had outdated effects? Utter nonsense. I think alot of people would have picked up Tron on DVD who hadnt seen it so the sequel would make sense. I for one have only seen Tron once, many years ago on tv and was planning on picking it up soon, to watch it before the release of the new film. Thanks disney you idiots.