In an interview with the Times, to promote his latest film, Downsizing, Christoph Waltz again asserted that he will not return as Blofeld in Bond 25.
Speaking to Kevin Maher, Waltz said:
"“It was an incredible experience to be part of this postwar cultural phenomenon. Yet I can’t say that I was happy at every step of the process. I feel that there are some loose ends with my engagement. And I’m not saying that I’m going to be in the next one. I’m not going to be in the next one.”"
It would appear that Waltz wants a chance to finish what was started, hence the “loose ends” part of this statement. However, what Waltz said next was more eye opening:

Winter is Coming
"“Let’s say, in terms of my feeling that I have sufficiently served a purpose, there are a few white blotches on that map for me, personally. I don’t want to be critical of something that doesn’t deserve to be criticized, so that’s why I’m being a little cryptic. There are just certain things I am unhappy with. I wish I would have gotten the opportunity to iron those glitches out.”"
Either Waltz is “unhappy” with how Spectre turned out or he is “unhappy” that he won’t have a chance to work on the character further. The difference is important, because Waltz already has a history of concealing things from the media. In interviews about Spectre, Waltz flat out denied that he would be playing Blofeld and insisted that his character was Franz Oberhauser. End of story. Right? Well, as it turned out, Waltz was feeding everyone some “misdirection.”
Related Story: Christoph Waltz not returning as Blofeld for Bond 25?
So…
If Waltz’s comments are meant as a criticism of the production of Spectre, then do not expect him back for Bond 25. But if he is merely demonstrating some regret about not playing Blofeld any further, then he may indeed be attempting to mislead everyone again. The Express makes a good point about this.
Stay tuned, as this story develops.