The real issue with Scott Pilgrim's licensing is that the original game was kind-of a promotional tie-in with the feature-length film. But the film tanked hard in terms of profits for Universal Studios. There actually isn't very much in the game as far as references to the film. The game is much more heavily inspired by the comics, and never makes reference to any of the actors in the film, and doesn't use any of the films audio or visual assets. Unfortunately, there is a Universal Studios logo in the intro credits sequence. So an original version of the game would require Universal Studios say-so, and they've been attempting to sweep that entire project under the rug ever since it bombed at the box-office.
Then there is also Ubisoft (the original game publisher), the actual game developers, Paul Robertson (the primary pixel artist), and the author/illustrator of the Scott Pilgrim comic. You'd have to wrangle licensing from pretty much all of them, and it is likely that all of them would want a cut.
It is most likely Universal Studios that is the primary obstacle. All the other parties involved have nothing to fear from the game cropping up again. The game got plenty of positive reviews when it came out, and is generally very well regarded by fans. It features great work by Paul Robertson, so he would likely be fine having it in more hands. And it would be a great promotional tool for the original comics, so the original author probably wouldn't mind having it re-released. No, Universal Studios is almost certainly the ones saying no. They've been trying to bury anything Scott-Pilgrim-related since their box-office bust.
