I think your review (in the sense of observing the trends and overall structure) of what makes a PbtA game, and then what makes one good on your two axes, matches my intuitions pretty well. I was also a little shaken by Uncharted Worlds apparent refusal to force an emotional or otherwise editorial agenda on first read, despite the fact that it really does seem like a cool game that is going to probably be fun to play.
I’m pretty excited to get UW to the table and put it through its paces, because like DW, I want to play a game in that kind of fiction, without having any interest to play a lot of the games that already occupy that space. The 2d6+stat tech, even when divorced from PbtA, really works for me, because it’s easy to remember and easy to teach, even when the outcomes are pretty trad.