[Crazy Jetty]

Uh, I don't think you understand how this whole "Making a movie thing" works at all.

The writers do not tell the director and actors what they need to do. If they did, they would be the Director.
Yes, the writers basically do just "write a book." They have very liittle to do with the final version, being kept on hand to make revisions. Many writers never have a thing to do with them after the script leaves their posessions.
The one who tells the actors what to do, who interperates the script, that's the director. They do not take orders from the writers.
There's a reason why writers aren't superstars, in the movie industry. (Certainly nothing like they should be.)
Also, all those movies you cite... Pearl Harbor, Armageddon, Daredevil... there's one thing that unites them beyond Afleck.
THEY'RE TERRIBLE MOVIES. Without Afleck being anywhere near them, they're still some of the worst movies ever made! Michael Bay directed two of them, for chrissakes.

Batman is not Ruined Forever because they cast Ben Afleck. (That is a general statement given how worked up and overreactive the whole of the internet seems to be, that is not directed at anyone in particular.)