It always seems disingenuous when people drone on about how bad BOTW is (weapons break! no traditional dungeons!), but with Mario Odyssey, I do think it's a game that people were very kind to when it first released.
I do think it's a good game and I had a lot of fun with it, but there are some big issues that just make it feel a bit off for me.
1) Absolutely no hierarchy for collectables. There is no way of differentiating a moon that was difficult to acquire from one that you just found lying around. Total lack of reward when I'm playing.
2) Too difficult to find challenging gameplay. I know the game was never going to be 'hard', at least until the post game. But there is too much randomly wandering around, hoping that the moon you're heading for will have some proper gameplay required to get it, and ideally some actual platforming rather than a mini game. Now that I'm in post game, I really enjoy playing the challenging bit of levels, but having to actually wander around the main level just to find the entry point kills all momentum.
3) The hat capture mechanic is mainly used as a gating device. Need to smash down a wall? Throw your hat at the creature next to the wall. Need to jump up to a high ledge? Throw your hat at the creature next to the high ledge. It's so boring and arbitrary, and there are limited opportunities to use the hat transformations creatively. It's not fun playing as a specific creature if the only role that creature serves is to help me along one specific path (before I'm forced to transform back into normal Mario).
As I say, it's good, but it's nothing compared to something like 3D World or the Galaxy games, which have proper difficulty progression and introduction of meaningful mechanics.