"Did the Scot win this year because Hazeltine is a modern course and, if our Ryder Cup players are any barometer, we seem to do better on modern courses?"
I don't know necessarily that he won because of the course, lengthier than the ones being discussed for Walker Cup competitions et al., though length may have played a factor. My sense was that he was a much better ball striker and more consistent putter. In particular, he was not as long as his finalist opponent, and thus usually was hitting first into the green, which is often an advantage in match play. One of the Golf Channel commentators (Chamblee, I think) talked about this and why Monty is such a great match-play player -- he's very consistent in putting the ball on the fairway from the tee, he hits lots of greens, and thus he puts constant pressure on his opponent(s). The Scotsman who won the AM seemed to have a very similar game -- fairways and greens, hope to sink a few putts along the way, and keep mistakes to a minimum -- in other words, be consistent hole to hole and apply pressure to your opponent.