It's funny that Catherine McEvoy was mentioned as someone who tongues, because it was a workshop with her back in the 1990s, organized by the late Bill Ochs, that convinced me to switch from tonguing to glottal stops! She said she occasionally uses her tongue, mainly on the highest notes, but otherwise she's always using glottal stops...even on staccato triplets (she recorded a hornpipe on one of her CDs where she does triple-glottal-stop triplets that sound very much like tak-a-dah tongued triplets); I have a recording somewhere of her demonstrating that in a class. She's also a great whistle player and does tongue when she plays the whistle. She is an accomplished piano accompanist too, but as far as I know she doesn't use her tongue.
Deirdre Havlin is a good example of an Irish flute player who uses tonguing effectively, it sounds fine to me in her style of playing.
Even though I came to the flute from the pipes, I'm not sure I agree that we're inheriting a tradition based on piping; Irish flute playing has evolved in its own way and if you listen to some of the standard-setters like John McKenna you'll not hear much in the way of piping in that.
I actually started learning tonguing again recently, but only for Breton music.