A Third Tron Movie?

According to Ain't It Cool News, Disney is very close to giving the next installment of Tron the go ahead.  This news come as a slight surprise.  While the movie has been successful, earning $300 million in theaters so far, it isn't exactly a roaring success.  Considering the effort Disney put into marketing and advertising, I think they were hoping for something bigger.  Why a sequel then?

Reason one is fairly simple: franchises are hard to come by.  Creating a franchise is a huge creative endeavor, and building a fan base is even harder.  Giving up on Tron means giving up a franchise and all the work put into it so far.  It's easier and less expensive to continue with Tron, as well as a reduced chance of bombing.

Also, we have to think about other ways the movie has been making money.  Have the toys been selling well?  How is the spin off TV series looking?  There's no way Daft Punk's soundtrack isn't selling like crazy.  Even if we ignore DVD sales, the film's actual intake might be much higher than expected. 

Overall, I don't know how I feel about this.  I know I'm not alone in feeling that the movie could have used a stronger plot, but sweet christmas did those light cycles look incredible.  Even if the writers make a smarter story, will the setting lose its novelty the second time around?  And where can the story go anyway?  Legacy didn't exactly set up a future for the franchise, and seemed to tell a fairly complete story.  Jeff Bridges is basically out of the story, and we've seen Sam Flynn resolve his daddy issues and even take control of his company.  Where do you take the characters from there?  I'm not saying a sequel is impossible, just that there's no obvious story to tell.  Tron 3 has yet to be confirmed, but we can at least speculate.