I couldn't take it. I felt like I was making no progress whatsoever. For needing 10 stars just to advance one galaxy, all of the World S galaxies were weak in some way. They should have been the best. Instead we got the Thwomp maze with terrible camera angles, a crappy boss galaxy, and while Rolling Coaster Galaxy was probably the best rolling ball section of the series, I can't really put it very high up because it's still a rolling ball galaxy. World S didn't do it for me, and I just realized how little I cared for most of Galaxy 2's levels. They felt like they were relying on gimmicks (the drill, 2d sections where the gravity changes, 2d sections on rotating cylinders, Flipsville, pushing snowballs around to make platforms over lava) rather than quality platforming. There were levels where you barely even needed to jump. I'll take good platforming over these attempts at "variety."
And I thought the art design completely fall flat. Aside from Hightail Falls, Tall Trunk, and Slimy Springs (everyone's favorite galaxy to mention for artistic design), it didn't feel like it was breaking new ground. And as for scale, did anything come even close to Buoy Base?
I liked the Super Mario World references, but as a whole the game completely fell flat. Like a series of ideas that they felt were underutilized or left out of the first game just mashed together with countless secret stars tossed in.
World S was certainly underwhelming, to think it actually starts quite promising but then deteriorates quite noticeably, having played Galaxy 1 to pieces stuff like the boss gauntlet and Stone Cyclone were like a kick in the balls as bonus stages. Wicked Wall jumps was great but I certainly agree that visually speaking it was blander than the blandest areas of NSMB.
I would completely disagree that Galaxy 1 had more platforming though, Galaxy 2 has stages like flipswap, beat blocks, cloudy court, clockwork ruins, the first star of melty monster galaxy and so on, you get the idea. SMG1 while certainly having its moments is quite content with more open areas, like making you collect 5 bits of a launch star far more often, having more frequent pull star paths and bopping between more small planetoids for the more linear moments, i'd say that all three of these were probably less frequent in 2 since the first game got more than enough mileage out of them. As such Galaxy 2 does feel far more obstacle course like, the worlds themselves are more like progressive linear paths floating in space while the first game has a similar approach but these various paths all hover over one large planet and are all visible from each other, see comparing Dusty Dune to Slipsand, both are desert themes but there is a noticeable difference to their layouts as an actual galaxy (see also Freezeflame vs Shiverburn).
World themes in 2 tend to take directly from the first game with spiritual succesors which means it lacks the same impact, as for your Buoy Base mentions, Space Storm galaxy was the follow up to that one, the second star has the same music and tasks you with climbing a very similar tower to that of Buoy Base, I just wish the storm was well...more stormy.
The gimmick point is interesting though and one that i've not really considered, Galaxy 1 has a bunch of ideas and gets a lot of use out of them but isn't quite as heavy with them, Galaxy 2 grabs new ideas frequently and doesn't quite get to explore each one fully as it always goes to introduce something new, more variety but missed potential perhaps, I feel 3D land took a few of them like the flipping platforms and beat blocks and pushed them to further usage. Personally I prefer that though, I love seeing something new in each stage.
You know I will say Galaxy 1 feels like a more complete and linked game so to speak while Galaxy 2 is a bunch of leftover ideas thrown into a melting pot but I really do prefer number 2 regardless, different strokes. What I actually find most interesting here is how two games that are so incredibly similar can have a few minor differences that manage to carve out a different identity to each other.