The biggest difference is that Marvel has taken some major risks, but also entrusted their characters to people who respected and enjoyed the source material and really got what made people read these stories for decades. The different franchises need different narrative voices to work, and the MCU has shown that. You couldn't have Guardians of the Galaxy done with the same style as Captain America: The Winter Soldier - they're just too different in tone. But with each being told in their own way, audiences got 2 extremely well done movies.
I think the biggest problem is that WB/DC is mimicking Marvel without grasping why it works. Batman v Superman is setting up to be a sort of Justice League movie, but they haven't bothered setting up all the characters, so it's kind of going to wind up being "Who the fuck are these guys?" whereas with the Avengers, they'd already established all of the characters, so they were free to tell the story without getting bogged down, and it gave you new character development by showing how the characters reacted to each other, and complemented each other's strengths and weaknesses. It wasn't "Iron Man v Captain America... and a bunch of other people." It was a bunch of individual heroes learning to work as a team, against an enemy that none of them could defeat alone. And it worked beautifully. This... I don't know what this is going to be, but if it's DKR, I'll pass.