Long tail SERPS are the worst I have seen this year for the last 48 hours.
We've been hit with dramatically dropping long-tail traffic as well. Yesterday was 3,300 referrals from Google from 2,000 keywords, compared to 3,700 from 2,700 a month ago. So that's 700 less long-tail searches, but only 400 fewer referrals, mainly because our short-tail traffic/ranking is actually up.
Long-tail traffic seems to get hit pretty badly for us with every update. It's as if Google resets the long-tail results and incrementally rebuilds them over time for each update (except this update seems to have been going on for a month now).