Ratings are one thing and usually the chaps conducting the survey seem to have been well fed by those surveyed !!
To get a reliable scope of passenger satisfaction, do the survey directly with passengers waiting to board their flight. Not with some survey international firm that gets perhaps free perks on writing about this or that.
When it comes to passenger comfort, much can be done at Suvarnabhum airport. Increase and open more immigraiton booths arrival and departure. Add more automated passport gates for all visitors on visa on arrival from western nations. No point in having luxury brand shops all over, when passengers often lack seating and device charging booths near the gates. Seating space, lacks at most of the departure gates and that highly challenges the results of such rankings.