Kevin R,
The 15th is hardly the most challenging wedge shot in golf for those who lay up.
It's a simple L-wedge or Sand wedge, depending upon what range the player most prefers to come in from.
The second shot at # 15 is duck soup if you're laying up, whereas the second shot at # 13 is not without risk, and the player can still be left with an uncomfortale lie, to a not so friendly green.
Until you've stood in the middle of the 13th fairway, with that ball way above your stance, looking at that creek left, bunkers, and reverse sloped green, it's difficult to appreciate how hard the shot is, especially if you're hitting a 3-wood, or very long iron. Pros recently have been hitting 7, 6, 5, and 4 irons into this green, and bringing them back to longer shots will enhance the playing value of the hole.
Mike, the holes aren't permanently altered at all. You and I can't even play from the Open tees at TOC unless we sneak on and don't get caught.
With regard to regrading the fairways, I'll have to reserve judgement until I can see the finished product and its impact on the hole.