I think I'm sliding to the "nay" side on this one again.
If we simply use <REF> and demand that only one of them have the body (which is true today), then we eliminate the need for another tag. Editors could take advantage of the feature simply by adding "section=" (or whatever) params to existing REFs with no other changes. And there's nothing saying you couldn't add one of these params to the "body ref" either.
But using <ref> for the "body ref" results in an unwanted [1] at the end of the article, and an unwanted extra letter in the references section linking to it. If people are going to be able to put all the references at the end so they don't clutter the article (something people seem quite keen on), there has to be a difference between how you give the body of a ref and how you create an inline citation. That can be different tags, or different parameters, either would work. Personally, I prefer different tags, since they are doing different jobs (and it's shorter that way).