I'm all in favor of this 'Snow Leopard' approach in OS 27. Really what more bells 'n' whistles do we really need? Consistency across platforms and underpinning all those platforms with lean, stable, architecture, eradicating pesky bugs et al, will establish a robust Apple Silicon based platform moving forward.
I'd personally like to see equanimity across the devices i.e. the 'Liquid Glass' effect prevalent in the iOS Phone app bottom bar being applied to the View toolbar icon set in macOS etc. What applies to one should be consistent with others. Similarly apps. I'd like to see the Health app on macOS for one.
I think we're getting to the point where the OS should be largely ignorant of the device and that the differential is defined by the interactivity with the OS. I can foresee a point where we coalesce to a unified AppleOS that applies to whichever hardware medium we choose to use.