I think a good possible route is for a more realistic turn to happen earlier. The problem with the Burton turn is the campiness of it all.
Campy eventually leads down that road to childness without correct artistic direction, which they lost when they sacked Burton.
The only way to really counteract this is by a more realistic strain of films also proving successful.
Still, it is not like there were no comic book films in the '90s....
I think the problem with the 80s and 90s is that the canon in the comic books have suddenly become serious, but for the general public the mentality is still that comic books are cheesy costumes and one- liners and not much else. The studios, writers and directors will also consider them as that, and thus do "moronified" things like the Schumacher Batman films and ignore the canon completely like Burton did in Batman Return. This in turn will probably give us movies that will be successful at first, as the general public like the gimmicks, explosions and cheesy dialogue, but the fans of the comic books will turn away from it, and very soon the super hero boom would just die, with every movie being pretty much the same, the general public would just be bored and stop going to see them.
Batman in 1989 did away with the cheesy, *biff* *pow* quality in the public mentality, at least where it concerns superheroes in film, and showed that comics could be serious and these were serious characters. Superman in 1978 also did away with it, and doesn't seem to get enough credit compared to Batman in that respect (Batman had to overcome the show).
What happened with the "moron" factor in the Batman films was not because the public was expecting *biff* *pow*; they already had that cherry popped. It was a natural thing of Hollywood trying to adapt to the audience. Batman Returns was too dark, so they lightened the franchise up. Kids love superheroes and parents groups were losing their minds that Batman Returns was as dark as it was and yet they were still selling toys and Happy Meals to kids based on that movie. That's why Batman Forever was made the way it was: it was made to be a more family friendly Batman. It wasn't campy. The camp came with Batman & Robin, which is totally camp. That camp came from the trend being going lighter and family friendly, a category of which camp falls in, rather than the trend itself being camp.
Then it came down that "This is too silly. Get serious." and we got the modern era of superhero films we have which started with X-Men and Spiderman, and continues up to this very day. To paraphrase Patton Oswalt, if I'm not confusing the quote of someone else, superhero movies took hitting that shit wall with the Batman franchise and that franchise failing in order to realize "we have to get to task and take this seriously" and that lead to X-Men and all of this that followed.
Don't get me wrong, a bad studio executive or director or writer or producer can still think of comics as campy like old comic books, and you can see bad films as a result of them doing them with that as the concept. I'm just saying Batman made it so that that was not guaranteed, and so that it would be their fault rather than the result of everyone thinking of comics that way.
Those bad people are the reason Batman & Robin was what it was. Those people are the reason Superman 3 and 4 were what they were, although that's actually the result of Richard Lester being a comedy director and going for slapstick and gags than him going for comic book camp.