I've seen plenty of photos with gents wearing kilts and sandals - I won't say it looks terrible but I have to admit I don't see me wearing sandals with my kilts. I suppose that paints me in the traditionalist category but there you have it.

I agree with Robin that its a visual thing. I think a kilt needs a good solid anchor to look masculine - boots or shoes with hose provides that visual anchor. One exception might be something like a pair of Keen cap toe sandals - discussed in a earlier thread.