I've been trying to arrange seating for a few weeks now for my DXB-DOH-JFK return in December and think I received my "final answer" as to why I cannot receive advanced seating at least on the DOH-JFK sector. In the manage bookings section of the QR website there is no option for seat assignment, so I did obtain seat assignments on the DXB-DOH segment (which books into F) on RJ.com, but even then would not let me select seats for the DOH-JFK (AA code share). I know there is an issue with lounge access when booked into R class, however, I thought I've read on FT that lounge access is still permitted with an AA code share booked in R class rather than QR R class. I guess I will find that out in two weeks. Anyway, to make a short story long I wasted about an hour of my life yesterday on the phone with the AA EXP desk home had to go through a supervisor and the one world desk to give me the answer that QR will simply not allow any advance seat selection for R class bookings no matter if it's an AA R or a QR R.
I guess if I can't stop by the QR ticket counter on my outbound and beg for mercy then I will take the advice and go to twitter at the 72 hour mark. I've noticed on EF that there are no seats available, but about half the cabin blocked!