Daniel Craig's final outing as James Bond will occur late next year, and in recent months, it looked like that Bond 25 was off to a strong start. Back in March, Danny Boyle was confirmed to be directing the movie (replacing Sam Mendes, who helmed Skyfall and Spectre) and working on the script with frequent collaborator John Hodge. But then it was announced this week that Boyle exited Bond 25 due to creative differences. That term is thrown around a lot in cases of a talent leaving a project, but in Boyle's case, it's rumored that the reason he didn't stick around on Bond 25 was because he didn't approve of who was being cast as the main villain.
There have already been reports about Danny Boyle having left Bond 25 due to the producers disagreeing with him about his decision to depict a "modern day Cold War" with Russia, but a source that spoke with The Telegraph claims that Boyle's exit was instigated by him not wanting Tomasz Kot, an actor who's starred in Polish productions like Spoor and Cold War, as the chief antagonist. Apparently this idea was considered a "left field" decision, and it sounds like Daniel Craig played a notable part in making it happen, as he has a "big say" when it comes to casting. With that in mind, Boyle's disagreement with Craig over casting could have been the ultimate reason why Boyle decided to leave Bond 25.
Keep in mind that this is just a rumor, and officially speaking, we don't know why Danny Boyle is no longer associated with Bond 25 other than the fact that he disagreed with its creative direction. That being said, I wouldn't be surprised if Daniel Craig does indeed have sway when it comes to casting for these James Bond movies, which can be problematic if the director doesn't agree with those choices. If Boyle didn't feel like Tomasz Kot was the best fit to play Bond 25's villain, but that casting was already set in stone, then he may have felt like he couldn't stay aboard the production in good conscience.
Whether Danny Boyle's departure from Bond 25 was due to a casting disagreement or something else, the movie now finds itself in murky waters. If MGM and Eon still want to meet that fall 2019 release date, they'll need to find a new director to fill Boyle's shoes quickly, otherwise a delay will be inevitable. What's also unclear is if the script Boyle worked on with John Hodge will still be used or if the one that Neal Purvis and Robert Wade previously wrote will be used instead. So far Daniel Craig is the only actor officially attached to Bond 25, although Ben Whishaw, who plays Q in this continuity, expects he will be brought back.