After doing Batman in 1989 and Batman Returns in 1992, Michael Keaton was all about doing a third Batman film, but he and Tim Burton wanted to do a thorough Batman origin story along the lines of Batman Begins. When the project was handed to Joel Schumacher, Keaton could smell the stink from 10 miles away and decided not to return to the Bat-cave.
Actor Hugh Laurie has apparently changed his mind about being in the Robocop remake, so the production has instead turned to Michael Keaton. House is out, Batman is in.
Even though production of Ghostbusters 3 has been hampered by the uncooperative nature of Bill Murray, in other overdue 80s movie sequel news, Michael Keaton is apparently thrilled and excited about the idea of doing a second Beetlejuice film. And I too, am equally excited at the idea of Keaton reviving the character.