The fifteenth is the par-5 along the river. We changed the approach and bunkering, and extended the tee back nearly 100 yards to make a better connection, after Art Hills had moved the 14th green a few years earlier.
As for your general question about working on older courses -- I have a lot of respect for older courses, and my associates really like to work on them to hone their skills and to get more familiar with the design concepts. Plus, the jobs are shorter and they are treated like kings, as opposed to the nine-month grind of construction on a real new course, which is often out in the boondocks somewhere and away from comfy living quarters and good food. [Bordeaux, where I am today, being a notable exception.]
Personally, though, I enjoyed consulting work a lot more 15-20 years ago than I do now. In most cases, the work just moves too slowly, and there is too much politics to cut through, when the really important work to be done takes only a matter of days or weeks ... for example, at Milwaukee it has taken four YEARS just to improve 3-4 holes, when we could finish the work on all 18 holes in a matter of a month or two if they'd just turn us loose. The change to #10 was very dramatic, because they had never paid attention to the view; but in general the changes we make are more subtle, and not as exciting, because we are not going to change the two elements which really make the course -- the routing and the greens.
I guess the truth is that for most of us it's a rare experience to get to build new courses which have the potential to be as good as the places where we consult -- but if you are lucky enough to get those chances, that's what we'd all rather do. The new courses are also fun for me because I have assembled so many good guys that it makes my part of the job relatively easy; I can be on site for 20 or 30 days and watch every green be shaped and adjust them on the fly, whereas the lead associate and shapers are there 6-9 months or more, and they get restless and tired of going back and forth to the same place.