That's rather good and I also enjoy Avengers: Earth's Mightiest Heroes
That said I wouldn't mind seeing a Flash film but only if he was up against The Rogues. However that might have one of the same problem as the Green Lantern in that The Flash (whichever version) doesn't remotely as much name recognition in the wider world as Bats and Supes do.
I'm with you on The Rogues, I think there's some interesting mileage in them.
Some heroes have a head start in that there is something about them that's instantly a draw, even if you've never seen them before. Everyone's wanted to right a wrong or something like aerial combat is big, showy and attractive. I felt with Green Lantern, there is more to explain about the story, so it's a few minutes in before the audience start rooting for him. Where as Spidey, Batman, Hulk have people identifying from the word go.
Can we share a moment for all the really bad superhero movies... we know who you are