In addition to some of the changes they highlighted on that show, the first fairway was narrowed, 40 yards was added to #4, fairway narrowed on #7, fairway shifted and narrowed on #8, new left tees built/rebuilt on #9, total redo of the 12th green, new bunkers on the right of the drive zone on #15, new addition to the 15th green on the front left (created a little plateau). Fairway narrowed on #16 with a new fairway bunker added on the left side.
Having had the opportunity to play Merion many times over the past 15 years, I'm actually surprised with how much they've changed the course in preparation for the 2013 Open. What's odd is that compared to years ago, quite a few of the preferred lines off the tees are now covered on rough. My preferred lines on holes 2, 6, 7, 8, 11, 14, 15 would now leave me in the rough on all these tee shots.