My shout, having only ever seen Medinah on the television:
1) bunkers are supposed to be hazards. The bunkers at Medinah appeared shallow and there appeared to be little problem for these players to play whatever shot they wanted from the bunkers.
2) what is the point of having every bunker surrounded by rough? It was clear that in every case a player hitting a poor shot preferred the ball to land in a bunker than the rough immediately surrounding it. The bunkers would have been more hazardous had they been filled in and rough allowed to grow in them. Bunkers at Medinah had become visual distractions, with the advantage to the pro that if they hit it in the rough and got lucky by finding a bunker, they wouldn't drop a shot.
3) the greens were, simply, too easy to hit and too easy to putt on. The first of these was, I suppose, at least partly due to the weather, but these greens were too soft. These guys could play any club they wanted at the greens and hold them. I read an interesting quote from Ogilvy (an intelligent and admirable golfer, I think) on Saturday where he commented that on one hole (I forget which) he had hit a very poor tee shot, which he would have expected to cost him a shot. However, he had been able to hit a 2-iron from rough (presumably the first cut or semi) and stop the ball in 12 feet from its pitch mark. As to the ease of putting, I can't recall seeing a three putt. Certainly long reange putts were routinely leaving tap ins. There were no greens where being out of position seriously threatened a three putt.
I'd like to think that the sport's governing bodies would look at Medinah and realise that length is not the answer to giving these guys a challenge. Sadly I expect that across the world plans are already being made for 8,000 yard courses.