Not experienced it myself but is it really fair to say 'dangerous stuff to be turning on your own under radorvectors in busy final environment' when the aircraft is on an intercept heading? You would expect the pilot to finish the turn onto the LLZ on his or her own - the problem that you have is that the aircraft is turning in the wrong direction!
I would be inclined to look upon this as a navigation problem and get it looked into. Have you reported it under your occurrence reporting scheme? Maybe your company could contact Delta direct to see if there is a problem that they can fix without difficulty?