In a new interview, Kick-Ass co-creator and 20th Century Fox executive Mark Millar--the man tasked with bringing The Fantastic Four and X-Men films together into the Fox corner of the Marvel Cinematic Universe--calls DC Comics's characters "out of date" and says that a Justice League movie would be "an excellent way of losing $200 million."
“I actually think the big problem for them is the characters are just too out of date,” said Millar, told SciFiNow. “The characters were created 75 years ago, even the newest major character was created 68 years ago, so they’re in a really weird time.”
Overall, his criticism of the prospective Justice League movie were practical concerns for the filmmakers, but ones that, when tallied up, could make the film very difficult to do without first having solo films to deal with these issues separately.
Millar said that it's difficult to create a convincingly visceral fight sequence for Green Lantern, whose power manifests itself in light constructs that make an up-close-and-personal confrontation unnecessary; that The Flash is too powerful for his villains and that his costume would be problematic to film.
“You can get away with stuff in comics that in live action’s just a bit sucky," Millar said. "The best one is definitely Aquaman. Aquaman can’t even talk under water. If you think about it in comics it’s fine, you just have a speech balloon, but how do you have Atlantis and people talking under water? Are they gonna talking telepathically? Is it going to be body forms? The actual logistics of each member of the Justice League is disastrous, and you put them all together and I think you get an excellent way of losing $200 million.”
Of course, such practical concerns as those could be mitigated by doing lead-in films to deal with those issues, or by making the Justice League feature an animated film.