Can't say I agree with the sentiment. Miryoku's layout looks pretty arbitrary, as is any other <60% setup. I daily drive a Planck (4 more total keys, but very similar levels of layout restrictions) and my layer designs are wildly different.
I would say just find or build a keyboard with support for Via or Vial so that you can change things on the fly when it feels wrong. If you're going down the small form factor keyboard path you're already committed to rewiring muscle memory, you might as well design your layout to meet your specific needs too. It's highly unlikely you will encounter someone else's Miryoku layout in the wild and need to type on it.
I don't think Miryoku is a good layout for many either, it will depend on your usage.
A strange thing is that many come in to the small split keyboard world and then don't have the motivation to come up with something that works for them. You can make anything work, so a lot make Miryoku work but I doubt for many that would be the best layout for them.
I code a lot and find that its layout would not suit me. I have 99% of what I need on a the base layer and one more layer for doing development work - on a 36 key board. I could not imagine that I would want to switch layers as much as I would have to for a continuous stream of alphabet/symbols and numbers.
I think Miryoku would be fine if you were an average computer user editing documents, emails etc and I do sometimes forget that there are a lot of guys out there using Miryoku doing only that.
I would say just find or build a keyboard with support for Via or Vial so that you can change things on the fly when it feels wrong. If you're going down the small form factor keyboard path you're already committed to rewiring muscle memory, you might as well design your layout to meet your specific needs too. It's highly unlikely you will encounter someone else's Miryoku layout in the wild and need to type on it.