Gosh, George, you are talking "earoles" instead of the other orifice you frequently allude to. Things are looking up!
But are you sure it's your ear that is dictating your choice? E major is mechanically an interesting key on B/C - I mean as regards fingering and bellows movements. You have often mentioned Soldier's Joy, in D, as an example of a tricky tune on B/C, from the mechanical point of view - the repeated D arpeggio at the start. Bump it up into E and you're laughing.
I discovered this when I learned (from member KLR) that Finbarr Dwyer played a certain composition of his in E mixolydian and not in D mix or A mix like everyone else. So I tried it in F# mix on my C#/D and instantly understood how he came up with this and others of his fascinating tunes on the box. Pull, pull, pull, yay, we're flying.
So maybe that's the fascination for you?
My favourite key for trad music - as far as my ear goes - is G dorian, but it does nothing to make life easy for a C#/D player, unfortunately.