A few quick observations:
I played every single Open tee except for #14 which you're not allowed to play. The only one which I saw as an issue was #14. On 14, the trees only come into play if you hit a low fade as your natural ball flight, they are not as tall as I remembered them. The member I played with told me that MacDowell played out there a couple weeks ago and it was a driver-3hybrid for him. It's going to be a bear! The new tee on 4 isn't a big deal, 50 yards longer but on the same line. The only problem is that there is a tree about 70 yards from the tee to the left which is merely a psychological hazard for tour-caliber players more than a physical hazard. 3 has a new tee which makes it a brutal par 3! For most of the guys it's a 3-wood at least. My host told me that the most likely setup was gong to be one day on the 275 yard box, 2 days one box up from that, and one day at the next box up. He also said that he thought they would make the 10th "very" drivable a la 7 at Olympic on the day they had 3 all the way back. 9 is a really long hole too! With the pin all the way back I had to hit a 2-iron to get there. Fortunately we had a lot of rain last night and I was able to stop it before it went into that back left bunker. 18 is ridiculously long from all the way back, it took a good hit off the tee just to reach the fairway. That said, I believe it returns the hole to its "intended" length because only the longest guys out there should be able to reach the slope.
The moved/narrowed fairways won't be a problem for the tour guys. Those who are familiar with the course are more thrown off than those who aren't. 2 is not as close to the road as I had imagined and really was not that much more challenging. A shot that leaks right will surely be out of bounds but there is enough room left that the players have a fair bailout. 6 was moved to the left a bit and makes it a tougher fairway to hit with the extra rough on the right. 7 is now right along the fence line which makes it a very tough 370 yard hole. One of the players in my foursome was in the right fairway and had to negotiate the trees. I was where the original fairway was to the left near the new tee on four and it is a difficult shot to get over that bunker now. 11 is now visually very confusing because it feels like a dogleg left, however the play is now to fire straight at the pin off the tee with an iron. Other than the confusion I don't think it affects the difficulty of the hole. 15 Hugs the fence line and the new bunkers definitely make the tee shot more interesting. I like to hit a draw off the tee and that makes this a very awkward tee shot for me.
The 12th green is noticeably more gradual. It is not ready for championship play but it definitely will be in time for the Open (probably will by the end of the summer).
This is probably one of the hardest courses under 7000 yards I have ever played. In my opinion the changes did not "ruin" the golf course. The only complaints from my host were about the different lines off the tee but as soon as he learns them I doubt he will see it as an issue anymore. The narrower fairways will protect the golf course and the greens are still fantastic. They were rolling about 10 or 11 today and still difficult. It will hold up next year against the world's best, I can see a winning score anywhere between -8 and even par.
Anyway, I hope I didn't say anything too controversial, feel free to ask questions as the course is as fresh in my mind as it is in anyone's right now. I had a great time and shot 74 in case you were wondering!