Another datapoint at HND yesterday arriving from SHA at about 5:20pm (early arrival), I went from plane door to curbside in about 5 min flat. Gate was adjacent to empty immigration and I had no checked bags. They had plenty of immigration officers twiddling their thumbs waiting for pax.
Always YMMV, but pleasant experiences mostly for the last year or two for me into NRT and HND with a few notable (and rather annoying) exceptions.