...apparently due to "creative differences between him and Ryan Reynolds".
Linky McLinkface
Deadpool was so good... slightly concerned about the sequel already having a "troubled production"; that never bodes well for the end product.
That said, I think Reynolds is very much inside the head of the character, he instinctually "gets" Deadpool and what he's about... so if the creative differences are due to there being something in the direction that Reynolds has turned around to and said "Nope... this isn't right... that's just not Deadpool" then I would be inclined to trust that judgement? I just hope they get someone on board who can capture the tone of the first film.