You also need to consider AC-branded cards for extra miles/points if you decide on AC and *A.
BUT if you are frequently flying to SFO from YVR, will you be able to get a US credit card? If so, you should look at staying with OW and getting an AS-branded card. AS was the best point accumulation for CX redemption.
Redeeming Asiamiles out of Canada for transborder is a PITA now.