I have tried two redemption trips since the devaluation and it was significantly more difficult -- and expensive. I saw no evidence of increased availability; quite the contrary.

I only look for business class roundtrip from North America. So perhaps there is increased availability in coach?

This whole "CHOICE/TAILORED" setup makes it even worse. I tracked this quite extensively the last quarter of 2018. In general seats would not open until T-40. And while some would release as STANDARD, in many cases they would only release as CHOICE, and once opened they would rarely drop to STANDARD.

That said, I'm still moving AMEX MM to AsiaMiles. I think there is more chance that AsiaMiles redemption seats will be available before partner seats are released. However, if I have time and flexibility, then I imagine it might be better (and cheaper) to book through partners.