Except for Tokyo/other parts of japan which is more bareable. unless you are looking into UO/HX or other alternatives that may involve going into china, tickets to Japan rarely goes below 3000HKD (with $0.1/AM valuation that percysmith quoted, and is the same that I was follow losely when buying miles. (i value them at least 50% higher when using, but with a discount for not actually holding cash and for future devaluation)) sometimes even when compared to the plane ticket portion of packages, since you may be able to go for cheaper hotels with sites like rakuten and jalan. count in the value of the dom flights, and the higher cost of buying a ticket to Haneda etc...

oh well i'm digressing... but this is where i think miles are of best use of AM from HK. I'd say, AM are best at:

most J and F travels

Peak season to Japan(all hk holidays when its not on wednesday, and the wkend before/after);
Peak season to Europe esp the UK (for UK it's June-mid October: summer start of school and uni, and mid-term for schools; mid Dec-mid Jan: Xmas travels and school end-of-term; early march: mid-term; and around easter: easter!) Actually i think this would work for students too since there's no change fee as long as they can book the out-bound leg and think of a way to hold the booking until the inbound leg opens up: but even for a 6M ticket the cost will be way too much to make miles redemption sensible.
Off-peak to japan is also ok, especialy if you can make the award ticket work with the JR passes. (full period whilst the train pass is active + use award seats to go there, llike for hokkaido)

i have also been in situations where the cheapest package was around HKD7000 (late booking yet there are J seats available for award). Hotel was not the big problem, so for the expensive plane ticket which i can now spend 50K miles for a J seat. still works within the range of the valuation of miles!