frankly, I don't think CX has made that much efforts in really trying to release seats for redemption. supposedly they have tons of past historical data to estimate potential loads and what # seats can be available etc (afterall I thought that's a key capability of an airline). and given there's always many redemption seats being released within ~2 weeks of departure, I really doubt CX's system really showed a few months ago that all these flights will be booked solid by revenue tickets eventually and so could not release any seat earlier - if so they really have big problem with their yield management system.

instead of really using the data to do some reasonable forecast and at least release a few seats for redemption, they choose to almost always not release anything until ~2 weeks within departure (this is a bit extraggerating of course, but close). well, their computer might tell them there's a 1% chance of a flight getting full eventually, but what they do is to bet on this 1% and want to maximize as much as possible so keeping every seat, instead of acting more rationally on the 99% probability that there will be seats available and that they could release a seat or two...

well, as a DM I feel less pain about this. but I just feel the pain to the more general public...yes, we understand we need flexibility in redeeming tickets - in terms of timing, routing, class of travel, etc...but if there's really nothing no matter how flexible you are, then I think the program will just more and more gradually be considered a scam...