Puzzle design is his strong point (and the team has several v. good puzzle designers on it), so it's safe to assume there'll be some good ones there. The sheer quantity make me wonder about how the game will be structured - they can't presumably all be stumpers (aka hard puzzles that you'll have to step back from and think about) - maybe there'll be more of a gentle flow between puzzles, like in the Witness, or maybe there'll be lots of optional levels/branching in the game design. I guess we'll see! I'm curious :)

Depends on your definition of fun. In both Braid and the Witness, eventually you come across a puzzle you cannot solve and have to use Google to find the answer, because the game never bothered to even hint at how it could be solved. That's pretty much the opposite of fun. Just pretentious; I would expect more of the same.