10. WB Would Not Even Try To Do Origin Stories
From a certain perspective, this is an admirable endeavor. We've seen Batman's origin on the big screen several times now, and the entire world knows that Superman is from Krypton. Various filmmakers have found different ways to tell them, to varying effect, but origin stories have been a staple of superhero cinema at least since Donner's Superman. Here's the other side of the coin, however: Martian Manhunter is a fairly major character, as is Talia al Ghul, Aquaman, the Wonder Woman... Sure, we're tired of seeing Batman's parents being killed, but I'm confident not everyone is aware of the fact that the Martian Manhunter can become invisible at will. Hell, I've been reading comics for a while now, and I'd be hard pressed to tell you how, exactly, the Flash's powers translated to his nephew Wally West getting them (and yes, he is in the movie). The problem is that the script is absolutely dense with references to previous storylines, with absolutely no explanation provided for any of the characters' powers. So, we sort of get, eventually, that I guess Aquaman can use his magical water hand to create constructs out of it, for some reason. The cumulative effect of this is if The Avengers was a direct sequel to Iron Man, with no further explanation. "Ever hear of comics?" the scriptwriters are asking us. "Maybe you should consider reading some, then you'd know what we're talking about. " They're completely ignoring the fact that while I may then read up on stuff I didn't get, most audiences just would not bother with the film as a whole.