I feel the example art here is actually one of the friendlier-looking renders of N64 Mario. I always thought the N64 Mario had more of an attitude, maybe just due to how the silicon graphics presented themselves, but I can't help it.
I also do want to see this iteration of Mario make a comeback. It's evident it's popular, given the amount of attempts by fans to try to recreate the look. I hope it becomes used as a nostalgic throwback the same way Classic Sonic was revived for it.
But don't forget his friends either! Luigi, for instance, had definitely a more circular face and more chin space as well as those eyes that look way different from Mario's eyes for the highlights being in the middle of the black region.
There is also Princess Peach, who had a bit of variance in the art, where her Mario Kart 64 iteration looked a bit plasticky, but she did get a better face by Mario Tennis and Mario Party. Her hair had one mote smaller front flips (as well as smaller and pointier flips) and was more rounded at the tip, I notice. Her irises were also smaller.
Bowser at the time was also some weird combination of scary but his proportions and posing look pretty comical. But who can forget the orange skin? And the bloodshot eyes. His maw also seemed less.... meatier too
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Ayyy it'll just be neat to see a modern throwback on the styles. It'll be a challenge to try to recapture the old feel but have the functionality of the new modeling techniques we have (this means probably no dislocated Bowser shoulders or dislocated thumbs, materials should probably also not be unrealistically shiny), but I can trust Nintendo to make an attempt and succeed.