Same here, flying SIN-HKG I chose an earlier 4:30pm departure to try to get the 77W. but got the 330 coffin seats in the end.
Another time gave up my HKG-SYD QF F ticket to try the new Cirrus product in J. Guess what - they changes the plane to an old 330 again.
Wrt to CX's regional fleet - they are really bad compared to SQ's. Are they actually thinking of refurbishing it though?