My vote: No. Nintendo’s been hard at work on the next mainline 3D Mario for over 5y at this point. I do not believe they would’ve spent all of this time merely creating a sequel to a (nearly) 20yo Mario game…though if they did, I don’t think any of us will be ready for the sheer level of quality that would come from it.

You never know with Nintendo. I personally would prefer a more open 3D Mario game like Mario Odyssey. I would love a remake of Mario 64 with all the remade levels as big as in Odyssey and where you don't get kicked out of the level when you collect a star. 

Nintendo historically doesn't really return to old ideas after they're done with direct sequels. They usually move to new ideas. Outside of remasters/ports like what they're doing with the first 2 games. So it would be shocking if they actually went back to make a new Mario Galaxy game. Would love it of course!

I wouldn't mind one of Nintendo's developers working on Galaxy 3 now for release next year sometime after the movie.  And the DK/Odyssey team gets to work on the true 3D open world Mario for 4 or 5 years from now.

No. No, they shouldn't. Galaxy had its time. Just make something new again. Wonder was not an NSMB sequel. Next Mario won't be a Galaxy sequel.

I fucking hope so. While I enjoyed Odyssey and I LOVED 3D World, I really miss the structure, mechanics, scope and soundtrack of the Galaxy games.

usually I'd say no, but it does feel out of left field for the Mario movie sequel to be galaxy based instead of something with 2/3/world
so maybe

I'd be down for both. Galaxy and 64/Odyssey are different enough. 

Galaxy is peak 3D Mario, so I would much rather Galaxy 3 than something in the style of Odyssey.

I voted for maybe with the movie/collection adding weight to that but I do hope that it happens for sure. Galaxy's design is still my favorite for 3D Mario.