If I remember the discussions correctly, on CX you need to have a K class (or higher) economy fare to be able to upgrade to business. I suspect the differences between K/H/B and the discounted Y+ class fares will not be all that dramatic.

Yes if I had my choice, K class SE Asia regional fares would credit to AA as a discounted economy class or ALL CX flights exHKG to Asia/SWPacific would have AA code-share flight numbers.

But no one listens, especially if you are wandering

Fred