I don't think I agree about the arms causing a loss of expression. If you see a really good dancer in a light shoe dance - she (or occassionally he ) will have an amazing abilty to just hang in the air. I think you wouldn't get this impression if the arms were moving. The related dance forms where the arms move such as appalacian clog give a totally different feel to the dancing. Most Irish dancers will dance SET and Celi dancing as well - so they don't loose out totally on the arm movements.

Julie