I watched the extended cut of Green Lantern last night and it's even better than the already-cool theatrical cut. There are more scenes of Hal as a kid with his dad, Carol and Hector that fill out the history behind the relationships so it doesn't seem as arbitrary when they are mentioned later in the movie. I'm not sure if these scenes would have saved the movie from the cinematic apathy that it received, but they are welcome improvements.
Speaking of Green Lantern's financial failure, I'm still flabbergasted that it didn't do better at the box office. Not only did I enjoy the movie, I thought it was much better than most superhero movies from both visual and storytelling standpoints. Thor, which had many more serious problems in my opinion, made almost half a billion worldwide while Green Lantern languished.
Maybe GL ultimately failed because:
1) Space-based sci-fi outside of Star Wars (and Star Trek, to a certain extent) doesn't sell nowadays. Sci-fi is pretty much limited to fantasy and Earth-bound superheroes, with some alien planet stuff (like Avatar) thrown in the mix every once in a while. Audiences just don't dig interstellar space adventures anymore.
2) The superhero genre was at its saturation point last summer, with GL as the third of four superhero movies released. Also, audiences aren't as willing to accept an unknown superhero outside of the Marvel Universe, which already has a cross-property story that connects newbies (like Thor) with more established properties.
It's really too bad that GL didn't do better, because I doubt we'll ever see Mark Strong strut his stuff as an evil Sinestro in a sequel. Maybe if it does well on home video there's some hope.