There are 2 choices to replace Batman and honestly either one would work. If your going younger or older. If your gonna stay with a Bruce Wayne in his late 30's and having done this for years then go get Anson Mount. His angry scowl and look fit the films. (Watch Hell on Wheels before you watch Inhumans though...)
Now if your going younger and if Flashpoint changes Bruce to a younger version of Batman ....then I'd go with Armie Hammer. In fact he was debated once for the role before they decided Bruce Wayne would be older. Hammer is 31 and has like a decade plus of Batman sequels you can do around him.
But whoever it is ...needs a good writer/director involved. Also Wonder Woman as a whole isn't Batman. The whole , well we need to inject more comedy only works on a small scale with a character like Batman. Its why Suicide Squad worked...it had brief comedy added later in reshoots that fit things. But it wasn't Guardians of Galaxy type comedy. You can't make every film fit a certain way.