I think the main thing that doomed the live-action movie was the title. Guillermo went in with his pitch:
GDT: "Today, I would like to talk to you about 'Justice League Dark.'"
Exec: "Soooo, Justice League."
GDT: "No, Justice League Dark."
Exec: "Yeah, that's what I said."
GDT: "No, you said Justice League. I said Justice League Dark."
Exec: "Gary, what did I say?"
Gary: "You said Justice League."
Exec: "So, I said the same thing?"
Gary: "Yes, sir, you did."
Exec: "Gary said I did, so, I did."
GDT: "You're talking about the Justice League, with Superman, Batman, Wonder Woman..."
Exec: "Yeah, same as you."
GDT: "No, I am taking about the Justice League Dark with Constantine and Swamp Thing..."
Exec: "Stop right there. I really don't know what you're talking about, now."
GDT: "They're the Justice League Dark."
Exec: "Yes, the Justice League is dark. We love how grounded and gritty they're going to be in our upcoming slate of films."
GDT: "That's a different thing."
Exec: "No, I don't believe it is."
GDT: "Yes, it is."
Exec: "With Superman?"
GDT: "Yes."
Exec: "So we agree."
GDT: "No."
Exec: "Yours doesn't have Superman?"
GDT: "No."
Exec: "So, who's in it?"
GDT: "Currently, Deadman, Constantine, Swamp Thing, Zatanna, Etrigan..."
Exec: "I still don't know what you're saying."
GDT: "They're the characters that make up my Justice League; from the comic, Justice League Dark?"
Exec: "I've never heard of any of that stuff before, but you can't call them the Justice League."
GDT: "I'm not. They're called the Justice League Dark."
Exec: "Yeah, our Justice League is dark, but Zack's already doing it. You're going to have to come up with a different name."
GDT: "Is Dark Universe good?"
Exec: "Seriously? Do you see Marvel making a movie called 'Marvel Cinematic Universe?'"
GDT: "I don't understand."
Exec: "You said DC Universe, didn't you?"
GDT: "No, I said 'Dark Universe.'"
Exec: "I LITERALLY JUST SAID THAT! ARE YOU ****ING WITH ME, RIGHT NOW!?!"
GDT: "I said 'Dark Universe,' you said 'DC Universe.'"
Exec: "You're repeating yourself."
GDT: "'Dark' and 'DC' are two totally different things."
Exec: "You just said the same words. I'm not playing this game, anymore. Gary, call Security."
Gary: "Yes, sir."
GDT: "**** you crazy people, I'm making 'Hellboy 3'..."
Exec: "Oh, and Gary, get me some more coke, would you?"
Gary: "Do you want it from the fountain or the machine?"
GDT: "...or 'Frankenstein'..."
Exec: "No, the good stuff. That guy really just stressed me out, man."
GDT: "...or 'Pinocchio'..."
Gary: "Ah, I understand, now. I'll call your guy."
GDT: "...or 'Pacific Rim 2'..."
Exec: "Thanks, Gary. Party at Tom Rothman's tonight, you there?"
Gary: "I'm down!"
GDT: "...or 'At the Mountains of Madness...'"
Security: "You called, sir?"
Exec: "Yeah, can you escort him out of the building? And, maybe, call an ambulance or something, I think he had a stroke."
Security: "Certainly, sir. Come with me, please, Mr. Del Toro."
GDT: "...or 'The Haunted Mansion...'"