Another update for Bangkok ...
"If one has time to kill at BKK there's an Observation Deck on level 7 - from Departures row 'Q/R' take the escalator up 2 floors and then a ramp from Cafe/Post Office. View of runways is not fantastic but a close up look at the building structure may be of interest."
I've never been at Bangkok long enough to have the time to investigate this, so it would be nice to get an updated report, even if it's just to say "it's rubbish!".