So I've watched most of the Treehouse gameplay demos that aired over the last few days on the Nintendo YouTube channel, and it took me a while to come to a conclusion as to how I felt about the sandbox-style design they're utilizing with Odyssey. At first I was concerned because videos showed several moons being acquired using no platforming whatsoever. With the larger areas to explore, checkpoints with fast travel, and "quests" being given by NPC's it was starting to worry me a bit. While I love the more open environments of Mario 64, I do think that Mario excels most when he's being put to the test in platforming scenarios.
But now that I've seen more footage of the game's various kingdoms I have more faith in the new direction in which they're taking the series with Odyssey. In recent years we've seen a small indie movement (led by the disappointing Yooka-Laylee) that seems to be trying to rekindle the magic of N64-era platformers like Banjo-Kazooie. Back then, the simple act of navigating a colorful fully-3D environment with smooth controls was novel and enjoyable, so most platformers of that era were collectathons that emphasized exploration as much (or sometimes more) than actual platforming. As Yooka-Laylee demonstrated earlier this year, that doesn't cut it on its own anymore. 3D Platformers today have to have solid, engaging platforming challenges to keep the player interested. That's where I feel Mario Odyssey is looking to bridge the gap between the two schools of 3D platformer design.
Odyssey looks to be Nintendo's attempt to inject that sandbox-style Kazooie level design with their trademark polish and knack for combining creativity with smart design choices. Whereas some moons can be acquired through simple explorative means, others come as a reward for clearing a wide variety of dedicated platforming sections. Hopefully they manage to strike a nice balance and the kingdoms don't end up feeling like vast spaces of emptiness with only a handful of platforming areas mixed into them.