Those characterizations have one thing going for them: there’s no Mill (yet); it doesn’t run any software (yet); OSs haven’t been ported to it (yet).
So, skepticism is healthy.
But I think they go too far in dismissing these ideas.
My favorite: “Lack of object code compatibility between different family members implies a more embedded universe for the product, where the application is known ahead of time and doesn’t change much”. Android proved that’s not the case 10 years ago.
In particular, the point you are quoting puzzles me. I’m not an expert in CPU design and _I can think of at least 2 ways it absolutely rocks_ (maybe I’m a sucker for immutability): instruction coding entropy and reducing the capacitive load (IIRC, there’s no big crossbar for 500+ registers).
The part about SAS comes up time and again. The Mill guys _did_ explicitly described mechanisms to deal with fork, relocatable code, etc. They simply ignore all that. Maybe they missed it, which proves my point: everyone has such a strong opinion while _at the same time_ admitting _hey, I may be missing something_.
It _is_ risky, of course. Let them fail. It’s not you, after all.