I'm really hoping for a string of bad ones in the near future, so the obsession will finally go away and comic book characters will return to being the works of comic book writers and comic book artists.
Just watch Game of Thrones. The Nords are the Starks. The High Elves are the Lannisters. You've got a contest of religions, influential magicians, alchemists, evil plots, the return of dragons, and similar symbology. You even get a good battle when the budget is available for it.
He has a functional knowledge of right and wrong, but will generally act towards his own goals. Smart characters (and most writers) will find some way of guiding Etrigan towards moral actions that still coincide with his goals.
It's really all about the execution. The right creative team can make a good movie about anything and the wrong creative team can ruin a perfectly good idea.
Did anyone in 1997 really believe that Blade would be the success it would be in 1998? That guy who runs around with the Midnight Suns and swings around a pair of cheaply drawn swords is going to be in a movie? Who would go and see that? No one who read the comics, that's who.
Up until their purchase by Disney, Marvel had one huge advantage: they could shop their properties around. Sony have a good script and director for Spider-Man? They can buy Spider-Man. Fox is willing to take a risk on a team-based movie like X-Men? They can buy X-Men. DC didn't have this option. All of their properties had to be done through Warner Brothers, and all of the ideas had to go through a very small number of producers that Warner's head-honchos assigned to the job. You can listen to Kevin Smith's rant about one in particular on his Evening With Kevin Smith DVD if you want. And so we got Superman pushing a mountain of Kryptonite in Superman Returns and Green Lantern making Hot Wheels tracks for constructs in his movie too.