I've HEARD:
NRT is much easier than HKG
YYC-NRT is super easy
YYZ-HKG is the worst, up there with YVR-SYD and some of the YVR-YYZ and YYZ-LHR routes.
That being said, sometimes, good things happen! I got upgraded today on the YUL-YYZ portion of AC 833, the very last J seat....granted, the flight got cancelled, but stranger things, like upgrades for E's to J on HKG flights, do happen, I'm sure!