I'm fine with Affleck as Batman, he was great. The problem is with DC and WB and how they're trying to catch up to Marvel's billions. This is all a rush job to them instead of taking the time they need to actually build the universe consistently from the ground up, as Marvel started off.
Right now I'd imagine the amount of executive interference and people calling, shouting, backstabbing each other behind the scenes at WB is what's making the job hard for anyone whose producing, directing, writing and starring in these movies. It's difficult to get a consistent tone and vision going everytime someone up the ladder decides things need to change because Marvel is doing this or that person commented on this etc.
Try been a writer in an environment where every week they want you to change and rewrite the entire script or large portions of it on a weekly basis. No matter how much I love a certain character, I'd say stuff it too and walk away.