Hong Kong also has that brilliant service where you can drop your bags off and check-in in the city in the morning, after you've checked out of your hotel. Then you can head to the airport and go straight through security onto your flight in the evening. Does any other airport do that?

Having been through Incheon quite a few times I don't see the appeal, at least compared to Changi or Hong Kong. I find Incheon huge, sterile and soulless, and I don't like the high-end shopping mall vibe. At least Changi actually feels like somewhere you can hang out for a few hours between flights.
you're in my hut now