Agreed, established cinematic superheroes, ie: any of the Avengers, Superman, Batman, Spiderman, no longer need origin stories, even in the face of a total recasting, just get a story and move on. Everyone is over origin stories.
Dunno: Batman already had an origin story done before Nolan came around, but Nolan's story doesn't work except with its origin telling specifically. I think repeating what other people have already done carries risks, the biggest of which is that its not enough to just be different, you have to somehow exceed what has been done in the past to not be a mere rehash. But I think all rules have exceptions, and the exception is that if you tell it right, retelling the origin story can have huge payoffs if its done right and done in a way integral to the future stories you tell.
Case in point, besides Nolan's Batman there's the Daniel Craig trio of Bond films, which have a certain feel similar to Nolan's Batman arc: its not just an origin story but almost the building of a myth. I've said before that Nolan's movies aren't exactly about Batman, its about a guy named Bruce Wayne creating the Batman myth. He has a personal story, but part of that story is that from the very beginning he intended to create this legendary figure that criminals would talk about like the boogeyman. What we saw was a man: Nolan's Batman is actually that statue they unveil at the end of Rises: a legend that grows with each telling of the story. In a sense, Daniel Craig isn't just a reboot, its almost the same thing: a story arc that sort of tells how a man went from being a gritty amateur to a seasoned veteran to James freaking Bond.
Most of the time, you're not going to get that kind of result, true. But on the other hand, if you don't allow people to try, you'll never get them at all.
