Deadpool director Tim Miller decided not to return for the sequel because of creative differences and says Ryan Reynolds wanted to be in control of the franchise. Reynolds was the one who spent decade trying to bring Deadpool to the big screen. Miller was replaced by John Wick director David Leitch and the sequel grossed $758 millin worldwide.
“It became clear that Ryan wanted to be in control of the franchise,” Miller said on KCRW’s The Business podcast.“You can work that way as a director, quite successfully, but I can’t. I don’t mind having a debate, but if I can’t win, I don’t want to play. And I don’t think you can negotiate every creative decision, there’s too many to make. So Ryan’s the face of the franchise, and he was the most important component of that, by far. So if he decides he wants to control it, then he’s going to control it.”
Miller added, “I’ve always been pretty good at the ‘moving on’ thing. I care deeply, and then you get to this point where you’ve gotta make a decision, and I’m pretty good about putting it in my rearview mirror. We had a meeting at Fox, and the writing was on the wall, so I said, ‘I get it. I’ll quit, and you guys can do what you need to do.’”
Now that Deadpool will be part of the MCU it's unlikely that he will be the point man on the series since Kevin Feige has the final say of all MCU details. The next Deadpool film will move forward under Marvel Studios.