Last time I flew into BKK (Jan after the SIN Do) I was on a CX flight in J. I was given an express immigration pass, the benefit of being One World Emerald.

So I was through immigration in seconds after taking a slow walk to the desk.
My case was waiting for me when I arrived at the baggage claim area.

No complaints at all.

Will be back there late May on a Jet* flight so will be interesting to see how long it takes if I check a bag.