The graphic enhancements are subtle, but very nice. The game is looking REALLY good now and I even turned bloom effects back on because they don't look so ridiculous now. The only high end options I'm not using are motion blur (because I never like it), and ubersampling (which my computer just can't handle). It's possibly the most beautiful looking game I have played that shoots for realism (insofar as elves and dwarves can look realistic).
Thankfully, most of the 4 hours of new content is added in chapter 3, and I'm only in chapter 2; so I shouldn't have missed much. There is more wildlife now, which is a nice touch. The new intro movie is amazing. And they even added a Playboy spread of Triss Merrigold in my bonus content section on GOG (no, really
).