INTs for and agains and passing TDs for and against are a big part of the quarterback rating differential rating you speak of. So by throwing more TDs and our defense getting more INTs is a big step in the right direction for improving that rating. All that's left to accomplish to get that rating to a superior level is to get the QB to cut down on the INTs. considering Tannehill is in his second pro football season, I'd say its very likely that he improves in that regard...Defensive interceptions correlate with wins at 0.41.
TD passes correlate with wins at 0.46.
QB rating differential, on the other hand correlates with wins at 0.81, and adjusted net yards per passing attempt differential correlates with wins at 0.84.
That gives you an idea of how some stats can be very strongly associated with winning, whereas others are much more weakly associated with winning.
Interestingly enough, Joe Philbin had his finger on the pulse of this in his introductory press conference with the Dolphins:
http://www.thephinsider.com/2012/1/22/2725109/miami-dolphins-coach-joe-philbin-introduction