I've flown AC's old A343 YYZ westbound to HKG non-stop (when the infamous A345 was "unavailable"). It's just a matter of compromising the load and range.

AC has also changed the departure time of its YVR to HKG flight from early afternoon to early morning. The change offers passenger from central and eastern Canada an alternate evening departure choice (with connection at YVR) than the morning AC15 departure (from YYZ).