This is a pretty common technique among the Czech nymphing crowd. I've done it a couple of times myself on swivels (used in same fashion you use the ring) but did not like how the dropper would wrap around the leader when casting in wind unless very stiff tippet material was used, so I went back to dropper off the bend. When fishing close or from a boat, this would be less of a problem, but for the type of nymphing/streamer fishing I do, a long cast in wind is inevitable. YMMV.