Don't believe (most of) the hype, I guess
SM3DAS is a lazy effort by Nintendo. Aside from tangential changes regarding controls and presentation, Nintendo did not improve the games in any way. They are direct ports. There is no Galaxy 2.
With that out of the way, here's my take on the games after playing through all of them to completion.
Super Mario 64
This was my first time playing through what is supposed to be a "pure" Nintendo 64 game. I 100%ed the DS port twice, and it was my first experience playing a 3D platformer, but having since then gotten used to full camera control in Super Mario Odyssey, trying to negotiate the right angle with the camera was a hurdle most of the time.
While that may not have aged well, SM64's brilliance still shows. The fact that this game managed to pioneer a genre is laudable, but the way it harmonizes its refined mechanics with level design that oozes with character must have made life hell for rival 3D platformer developers of the generation. In 1996 Nintendo essentially went "here's Super Mario fucking 64, follow that", and their hand was so good that it is hard to think of anyone who has beaten it since then other than Nintendo themselves.
Super Mario Sunshine
Even though it was my first time playing through a Gamecube game, the experience was undeniably spoiled by me having watched the entirety of Steal My Sunshine.
In terms of pure playing, SMS is a joy. I would have had a really bad time if they had kept the camera controls inverted, but aside from that (and small instances of geometric jank) the controls are tight and responsive, and FLUDD is a gimmick that actually adds to the experience.
My only issue with it is that it lacks the innovation that SM64 brought to the genre. With the exception of the receding walls of Noki Bay, the levels are forgettable, a collection of missed opportunities. Delfino Plaza, Ricco Harbor, Pinna Park, and the hotel are great ideas for levels that fit the seaside theme, but nothing was done to make them unique experiences. The rocket nozzle and the turbo nozzle are cool, but not much was done to justify adding them to the game. The blue coins would have been fun to hunt if they had named each of them and made a list for each stage.
Still, it is very easy to get past the fact that this game could have been more than it is. Just because it is not groundbreaking, it does not mean that it is not a ton of fun, and it stands the test of time better than SM64 in more ways than one.
Super Mario Galaxy
This was my first "pure" experience with a Wii game.
I wish I could go back and erase 13 years of hype surrounding SMG. It brings back the innovative mechanics and *ahem* STELLAR level design that we have come to expect from a mainline Nintendo title, but I did not have as good a time with it as I did with SMS.
There is much to be lauded about SMG. It is fun, it controls well, and when the gravity mechanics are used to their full creative potential, the game is amazing - in fact, so good that it feels even more of a missed opportunity than SMS. At least half of the levels feel like tech demos or hastily slapped together areas, like the beehive-themed ones or the purple coin sections. Inexplicably, many areas do not give you full camera control. Plus, both the motion-controlled areas and the post-Luigi content are unnecessary.
Individually, these games were more enjoyable than frustrating, each for different reasons. The compilation should have been priced at $30, and Nintendo should have made more quality of life improvements to the games. It has to be said, however, that they are all great, and definitely worth playing if one is of the 3D platforming persuasion.