I totally agree with you with CDG for most parts (except new AF 2F) dreadful and I have to endure it once or twice a month! The lack of decent food outlets in a world culinary capital is unforgivable!
Even as a Hongkonger I must second on you about Changi for being the Best in the world. Nothing beats the Koi ponds and the tree fern tropical gardens!
Hong Kong might be looking tired now (like cats and dogs 14 years is very old!) but the fact that it is constantly upgrading itself is the secret of a well run airport.
Changi is a shinning example of a 30-year old airport still beating the other new entrances!