Deadpool's charmed life seemed to be continuing into development of it's sequel until it hit a not minimal bump in the road when it lost director Tim Miller. The reason given was the main reason anyone gives for leaving a film project, "creative differences". This is basically the same catch-all that "irreconcilable differences" is used for in divorces (and equally disingenuous).
To be fair, Miller hadn't actually inked the contract to direct Deadpool 2, but he had been involved with the script development and all signs from him (as well as everyone else) were that he was going to be sitting center chair. After all, he and star Ryan Reynolds had managed something that Fox had only been able to do once before – make a really good X-men film (yea, sure it's not part of the X-series, but let's pretend it is so we can say there were two good ones, rather than just one).
Now the separation is going better than most, as both Reynolds and Fox continue to speak highly of Miller and his contributions (in many cases the Studio will simply excommunicate the person in question and pretend they never existed).
In an interview with CG Garage, Miller and Joseph Kosinski (Tron: Legacy, Oblivion) spoke about a range of topics, but when Deadpool came up, Miller had this to say:
I haven't talked since Deadpool 2, I stepped off the movie. I just want to say one thing to our geek audience out there, because it's important to me what the geeks and nerds of the world think, because they are my brothers and sisters.
I didn't want to make some stylized movie that was three times the budget, and if you read the internet – and who cares, really – but for those of you who do, I wanted to make the same kind of movie that we made before, because I think that's the right kind of movie to make for the character. So, don't believe what you read on the Internet.
So, he's saying that he wanted to make another film along the lines of resources and feel of the last one, and that he was feeling pressure to scale the production up significantly (he mentioned 3x) and to stylize it (read: in the school of Fox's superhero-film-making-darling Bryan Singer).
The strange part of that is that back in late October, TheWrap had an "individual familiar with the project" tell them:
In initial sequel talks, Reynolds, Reese and Wernick envisioned a "scrappy," raunchy and inexpensive movie, the insider said — in the vein of the first, which earned over $780 million worldwide on a $58 million budget. It's a stunning return on a film Reynolds lobbied 11 years to make.
Miller, known more for his visual flair than for the brash antics that Reynolds and his writers embraced and that fans loved, wanted a more stylish take, one that would compete with mega-budget superhero movies, insiders said. But it would have cost three times as much as the original $58 million film, the first individual said.
Ok, so that gives us two different sides, both seeming to express the reverse of each other – "we want cheap, lean, and mean, the other folks want huge budget and a different vibe". So, which version is it?
It does still seem highly magnanimous with lots of refrains of Kumbaya as Miller continued talking about the remaining Deadpool 2 production team:
I wish them nothing but good — I hope it's great. I hope it's a great movie. Because I love the character and I think it's great, and I love all the actors and I want to see them successful again. I haven't met David, but he's a great guy from everything I've heard. I want nothing but the best for the character. And for Fox, too. They deserve to make more money. They need to make more money [laughs]. They were great. They were terrific.
Regardless, both sides will likely very much land on their feet because Deadpool 2 will invariably break records on their opening weekend (whenever that gets around to happening). Miller, for his part pivoted immediately to another priority Fox project, an adaptation of Daniel Suarez's cyber-crime thriller Influx.
You can watch the CG Garage episode in full below, and the relevant Deadpool parts are at around the 45 minute mark.