I've been fortunate to play a goodly number of courses that have had some significant work done in the past few years. Six that I have some experience with are Philly Cricket, Oakland Hills South, Naval Academy, Eisenhower, Pinehurst #4, and Baltusrol Lower. I had liked Cricket before the work was done, but loved it afterwards. The opened vistas made more of a positive change than I thought it would. The conditioning is some areas was much improved.
THe first time I played OHS I didn't like it much at all. The bunker work that was done and the tree clearing were exceptional. I had forgotten how good the terrain is. It felt more playable as well, although without a good caddie the greens would have made me look silly.
Baltusrol Lower was so much better that at times I thought I was playing a new course. It was always very good but the work that Hanse did bumped it up a bunch. Holes 2,5,7,15-18 were just enough different to make me want to go right back out. I think 15 is my favorite hole on the course. The tee ball is demanding and the green is exceptional. If holes 7-12 were on more interesting terrain I would like it nearly as much as OH.
A couple of weeks ago my wife and I played Kyle Franz' just finished work as Southern Pines. I had not played the course previously but had seen pictures. It is now outstanding. The terrain is much hillier than I had thought and the bunkering is just exceptional and in well placed in locations. I had a bunch of sand in my shoes after the round. The par threes were excellent and the short par fours fun. It will make a nice complement to Mid Pines and Pine Needles.
I played #4 a couple of years ago. I loved it in the early 80s, didn't like it much after Fazio's work, but fell in love with it again. For me it was almost like playing a new course.
Other courses that worked are the Naval Academy, nearby Eisenhower, and the totally redesigned Birdwood Course at UVA.
We are living in some great times for sprucing up some older courses.