The other day I saw the Dark Knight trilogy collection in the store and it made me realize something: Superheroes are inherently ridiculous concepts by nature no matter how realistic you try to make them. If the franchise had gone on any longer, they would have had to break out the more silly villains defeating the purpose of the "realistic" tone of the movies. There's a reason we aren't up to Dark Knight 5 by now: He'd be fighting Killer Croc and Mr. Freeze again. No, it probably wouldn't be Arnold in the suit but it would still be making an appearance none the less. Thus everything Nolan was trying to achieve would go out the window. This is true of any super-hero no matter how realistic they try to make him. Look at what Byrne did to Superman. He made him as realistic as you possibly could and it ended up stripping him of a lot of his support system. Krypton was a wasteland long before it blew up, his childhood was normal (read: boring) and half his supporting cast was either thrown out (Krypto, Supergirl, the Legion) or changed to completely different characters (Lex Luthor, the Kents). The problem with this is that sooner or later, someone like Mxyzptlk shows up and all of the sudden a flying dog with a cape doesn't seem so ridiculous after all. There's no way to keep it truly "realistic".
David Mazzucchelli went into this somewhat at the end of Year One. You can do a realistic story up to a point but the moment Bat-Mite shows up, it lessens the believability of the realistic story somewhat. Or, to quote Mazzucchelli himself "The more realistic super-heroes become, the less believable they are". Mike Grell made Green Arrow realistic almost to the point of taking him out of the mainstream DC universe altogether. But Superman was still flying around out there somewhere. The trick arrows were still a part of his history. Ditto the Arrow TV show. When it debuted two years ago, he was the most realistic take anyone had done to a super-hero. Even more so than the Dark Knight movies IMHO. But Green Arrow doesn't have a huge rogues gallery to begin with so he became kind of a stand in for Batman. Huntress, Ras Al Ghul and the League of Assassins, Deadshot, all made appearances and pretty soon he was living in the same universe as the Flash and the Atom and, depending on how the whole Supergirl TV show pans out, possibly Superman. Hawkgirl is going to be part of a spinoff show this fall.
Ten years after the Byrne reboot, the writers of the Superman comics were trying to find ways to force SA elements back into the comics. They ran out of ideas because they ran out of toys to play with. The Daredevil show is really good but it still takes place in the same universe as the movies and again, how many enemies does he have they can tap into without bringing the rest of the Marvel universe in to play with him? I hear Punisher is on tap to show up next season. Sony ran into this problem with the Spider-Man franchise. They wanted to do spin-offs but there was no one to spin-off to besides villains. The idea that a number of super-powered beings with unrelated origins showing up at the same time is not the most believable concept to begin with. The X-Men are about the only ones who can pull it off and that's only because people are born with powers there. And most of them aren't believable. Guy who heals from anything and is semi-immortal, not the most unbelievable concept. Guy whose skin turns to steel, not so much.
The system is set up so that you have to live in a universe with other heroes and over-the-top villains in order to stay interesting. Nobody wants to see Superman or Batman just catching burglars and purse snatchers all the time. I'm not trying to bash super-heroes; I love comics and super-heroes, but there seems to be a push to try to make them more and more "realistic" and it just seems like you can only go so far before you realize, hey, they're just a bunch of grown adults running around in masks. I don't know if you'd qualify this as a rant or what but it was something I thought about the other day and wanted to get off my chest.