I think that Nolan being involved will make it more grounded in reality. The character itself does not have to realistic because of what he can do; however, his personality and everyone else around him in the movie should have realistic personalities. It is normal for people (especially if someone could fly and be immortal and do all of these things) to want to explore the world. He might just have a job as a fisherman, he might have started out there, he might be a journalist traveling the world, if this were set in West Africa, everyone would say "Oh cool, it was in the comics, so that is okay! Go Nolan!" but if it is set in an Alaskan fishing town, then, it is weird.
I think Nolan's involvement can only help hammer the point home that the acting should be realistic. That the camp is out. That if there are elements from the comics that are corny, well, if they need to be in the movie for the story, improvise and make them as acceptable to today's audience as possible. If it can't be done (like Robin) then it doesn't have to be in the movie. I understand comic book fans like the comics, but this is a movie, not a comic. A movie based off of a comic. Every movie based off of a book has to have some freedom to make changes. "Inglorious Bastards" made quiet a few changes from the pages of history, and no one seemed to have a problem with it. "Amadeus" was different from the pages of history. "Jurassic Park" was different from the book, etc. I don't see why a movie can't be different from the comics.