The question that I find myself asking is: How abrupt are the transitions between these wind speeds? A 200-knot wind at 30,000 feet should be harmless enough in itself (albeit frustrating if you're trying to fly against it), but an abrupt transition between a layer at 200 kts and one at 180 kts could be pretty scary. A change in direction would be equally unsettling.
So ... how abrupt are the transitions at high altitudes? Can you feel it (I've been a passenger in airliners and felt turbulence, but of course I had no way of knowing wind speeds at the time)? I seem to recall reading that the transitions were a significant source of CAT.