Quite a simple idea this one. Make a Mario Maker game but using Mario 64 as the engine/environment/assets.
So you play through Mario 64 and each stage you complete you unlock the assets for, the tutorial being the first stage (rather than the hub).
It would include up to 4 player simultaneous multiplayer functionality for no practical reason just for kicks.
As with Mario Maker at finishing the tutorial it would unlock a few ‘concept’ levels with basic assets.
So your probably thinking, “this sounds stupid! How would you easily make a level of 3D Mario?”. It’s simple when you think about it, the same as any tony hawks/doom/single player level editor; Snap ability for objects to terrain (running on a grid based system) but able to turn that off and “click” objects together easily without. Uses white gloves hands to deform objects the same way Marios face at the start (and also smart phones/touch pads with 3D). Essentially the only requisite is a start and a finish (star) and each level can only be published if the creator can complete it.
There would be a simple story setup for levels, i.e. You can either create a hub and branch your other levels from there (with the same “must have start and end validation check” or upload levels as a stand alone experience. Potential for a low polygon version of all 3D Mario hubs to be included so Delfino plaza and the ships from Galaxy.
Oh and an obvious return of amiibo support characters as playable characters or additional npcs for the hub and possibly some additional assets added (so say link amiibos unlocks a Zelda hub).
So production; One simple rule, “keep it simple”. So the editor would need to be easily accessible with a camera that could snap to x,y,z, pan around or wire-frame at a click. The assets would need to have a severe polygon limit to fit the aesthetic also this would help make up for the fact that this would require a crazy number of assets to be built. The music and sound effects, exactly to the point and simplified but only to an n64 era level. Essentially the editor would come first, then the assets and then building the Mario 64 game in engine.
So why not? It’s a me Nintendo! Enjoy your cease and desist. Would be nice to see Mario Maker get a sequel though.