I've been dancing and playing for various types of morris for nearly thirty years, have been fortunate to find teams with vim, vigour and imagination and I feel that, danced properly, there is no other national traditional dance which can compare for energy, dynamism and impact.
As regards the origins of tunes, I'm with Alistair Anderson (I think) who said something along the lines of "it's not where it comes from but who is looking after it." I've played Irish tunes English-style and vice versa in sessions, both knowingly and unknowingly, I'm sure. I tend to regard the Irish style as "warp eight, Mr. Sulu" with ornamentation in the melody and very little accompaniment, whereas with English style the ornamentation can be much more in the accompaniment, chords, counter melodies and harmonies. My view, not necessarily rooted in tradition, although a reflection of what the English greats (Kirkpatrick, Carthy etc.) do. I find fast diddly-diddly sessions pall after a while, all very same-y.
Can you beat English song for variety? Wide harmonies in the big chorus songs, dark ballads, rude, lewd and comic songs, such beautiful use of descriptive language in so many cases from supposedly uneducated peasants etc.
The other thread seems to be cycling round the theme that "Celtic" is a misnomer for a lot of music but is used to make it marketable in a musical world where "English" or "British" are not held in high regard. Such a shame when there is so much great music to hear and get involved in.