Disney won't sell the TRON license unless it needed a lot of money very badly very quickly. Odds are, that will never be the case. However, just out of curiosity...When was the last time Disney sold ANY license that it had developed to anyone else?
As for a new movie...What would be the subject material? TRON came out when the personal computer was emerging in the home market. Arcade machines were popping up in places where you'd never suspect they'd be. It was as good as perfect timing as you could get from Hollywood.
The sequel to TRON missed a golden chance to premiere with the rise of the Internet in the home market. That was around anywhere from '94 to '96, depending on who you ask. Now that the Internet is old-hat, what would TRON debut with? The rise of Open-Source software (a little late for that at this point)? Bio-tech (hardly a concept a mainstream audience would relate to)? The emergence of rampant viruses & other attacks against the Internet (the sequel would have to hurry to jump onto that bandwagon & TRON v2.0 already did to a certain degree)?
It would be nice to think that we could somehow put the genie back into the bottle. Computers were new for a lot of people in 1982 & it's world seemed limitless. We're a bit more jaded now, naturally, as we've had to keep pushing the boundaries of what real computers could really do. A proposed TRON 2 movie deserves to entrance it's viewers by exploring a world that, we ourselves, have yet to begin to explore. A chance to begin again in a golden land of opportunity & adventure. (OK, I just had to slip that one in.)