The Lv70 WHM relic gear is prettymuch unwearable because of the fan collar they put on the female version, which clips in a really awful-looking way. I've never seen anyone using it.

I don't know if a removable collar toggle is possible, but if it could be done I would love to see it happen.

Actually I'd like to expand that idea to be a "one removable element" toggle. It could cover things like the giant bow on the Gold Saucer bunny vests, the skirt part of the Thavnaairian sets and similar, and all sorts of interesting things that could bring variety to costumes without adding more items.