For a better description Evan, and as someone that has played both of the courses many times......
The greens were all basically raised-up about two feet or more in some places. To do this, he excavated these huge pits near the greens for material to do so, (or so it would seem) creating what I feel is some bunkering that is totally out of character of the original Bell Jr.-mode, which Rees actually claimed he was honoring during the remodel. Are the greens better? No. They are not, they are tougher, but not better then the subtle slopes which used to be actually quite fun to putt, even with green speeds at 7 or 8 on the stimp, which the old ones used to get sometimes because of excess play.
However, Rees did create a much better golf hole at the 14th. There is no doubt about it and he is to be commended there, but the next question is, does it undue what he did on the 13th, which was one of the more interesting par 5's on the South Course. The "terraced" bunkering is totally in tune with Rees design style, which of course justifiably doesn't receive much praise from this website, and looks about as much in place to the nature of Torrey Pines as a Dunkin' Donuts would be at the entrance to Magnolia Lane.
Other bunkers on the course are just as bizarre, one looking like Rees was channeling the spirit of my late dear friend Desmond Muirhead, wanting to construct a bunker shape in the form of a mechanical shamrock. (@ the front of the green on #8)
All in all, the entire procedure of making the course into US Open course has been somewhat taxing to all involved--poor turf conditions throughout; thick rough grass which has added to the pace of play which was already bad before Rees got there.