That's great, but I'm confused as to your point
Are you for raw, against it, neutral?
I feed a high quality kibble and my greater swiss mountain dog has an awesome coat. I've fed raw before and the dog I was feeding it to looked great.
I really can't imagine a kibble, even the cheap stuff, and raw causing a horrible coat on its own, it sounds like there was some kind of other neglect going on. Like they weren't feeding the stuff properly in general and weren't caring for the dog and its coat. I haven't had a sheltie, but they have a similar coat to a rough collie (which I had and now my mother in law has him) and if you don't rake their coat out daily, exercise them and feed them properly they will get hot spots or chew on themselves and their coat will just look crappy. My mother in law missed a knot on his butt and he got a hot spot there and now he's fur looks really bad there (well before we shaved the fur off to treat the spot, so now he looks worse
So yeah, point is, just not sure what you're implying about the dogs coat? What do YOU currently feed?