Ugh. If ever there was a movie that didn't need a sequel, it's this one. The whole thing is just a big indication of what's wrong in Hollywood right now: there's too much emphasis on style over substance (Avatar, I'm looking at you), and on sequels/remakes over new ideas. I halfway understand at least the temptation of the second one. You figure, it already has fans, those fans will go see it, thus it will be a success. But the producers forget that fans are cruel, they're hard to please, and catering to them is tough business. Those who aren't fans won't see it if they think it's too geeky or prosaic or anything else. And the fans themselves won't see it (or will at least cry "ruined forever") if they get the slightest hint that something of the original was changed.
But this style over substance thing, that I just don't get. Yes, good looking effects can define a picture a la the original Tron (and to a lesser degree, the sequel). Give it a few years, though, and it will look dated. Such is the nature of technology. And if you build your entire film on its look, eventually it will be outdated, too. The things people remember, the things that resonate the most, are stories and characters. That's why films like Casablanca and Citizen Kane consistently make "Greatest Movies Of All Time" lists. Good writing is never outdated.