I've probably said this a million times but I just can't get into these games anymore. They're such a chore to replay. Not just because of all the load times and getting kicked out of levels, and not just because they have the least interesting moveset and worst powerups (though that's certainly part of it), but because the game is linearity on top of linearity topped with too much simplicity. People like to say that linearity isn't bad, and that's true to an extent. But when done the way Galaxy does it, I find it pretty boring. On a first playthrough it's really fun because they really do throw new things at you all the time. But on repeat playthroughs the game doesn't offer up enough variation or options to recapture that fun, or to make gaining a better appreciation of the systems rewarding. It's fine to have linear level design, lots of games do. 3D Land/World have that too. But Galaxy doesn't just have linear level design, it also has linear objective design. Which is to say, not only are you just getting from point A to point B, you're getting there by doing very specific tasks that offer little to no room for variation, expression, mastery, etc. Not only that, but the tasks they ask you to do are usually very simple and easy (shoot fire at the torch to open the door, float on the dandelion to get to the next planetoid, climb a wall as a bee very slowly with not real obstacles). And to top it off the game is also just as incredibly easy as every other 3D Mario not named Sunshine.
So yeah, I found the Galaxy games to be incredibly fun the first time through because the sheer variety of sights and sounds kept me engaged. But going back to them they offer very little in the way of what I would consider to be meaningful gameplay because they double down on linear level design, linear objectives, and then they make those objectives simple, obvious, and easy. I really don't think they hold up as well as people say.