For me, a kilt is about being self-secure enough to wear what is comfortable, not what is normally done. In Fairbanks, I wear trousers all winter. For all the claims of the warm air rising and keeping the legs warm, I have to note that there isn't any warm air to rise (at least outside - I do wear a kilt indoors while bumming around the house).

(WARNING! Graphic implications ahead!)
Since I started wearing a kilt regularly, my jock itch cleared up, my occasional discomfort from "too much pressure on the boys" happens a lot less, and the leg hair that jeans seem to rub off of my legs has grown back. I suspect that if I went back to all trousers, all the time, that those health benefits (small and anecdotal though they are) would go away.

I think what would bug me the most about not wearing kilts anymore is really that I would feel like I was afraid to dress for myself and feel that I was instead dressing to please others. And that would be sad.

-Patrick