How can somebody with such a username be so wrong about Mario?!
Nah it's the truth man -- in fact the only 3D Mario game I'd say 64 is definitely a better game than is Sunshine.
Again though, no disrespect to Mario 64 -- it's really great and does still hold up reasonably well, and is an absolutely staggering achievement for 1996, a company's first real 3D game, one of the first 3D platformers, the industry's biggest IP moving to 3D, innovation, etc. etc. But Nintendo themselves have far surpassed their work on it multiple times with objectively better 3D Mario games.
It's also like saying Super Mario Bros. NES is better than Super Mario World and Super Mario Bros. 3 and they should just remake that for new audiences since it's never been surpassed. It's just not true. It's a fantastic game for many of the same reasons as 64, but they refined it and have done better since.