"Constraints breed creativity."
The new Mii editors in games like Tomodachi Life: Living the Dream and the Miitopia remaster are impressive, yes. More tools, more freedom, and everything looks better. But I think they miss the point of Miis.
The thing is, as mentioned in the title: constraints breed creativity.
Sure, the extra tools are nice. But it's fun, challenging, and more impressive to create within the boundaries of the standard Mii creator.
For example, take this TV host Mii:
That's impressive because of the limitations, not in spite of them.
Same reason people still enjoy making things in old game engines and consoles, or why pixel art is still huge. The constraint is part of the craft.
With the new editors, you could just... draw it. And yeah, it'd probably look better. But looking better isn't the point. The point is making something recognizable and expressive with the limited tools at hand.
Constraints breed creativity: and taking the constraints away takes something with them.