Brian, Not really a big deal but...Did you do a search within the discussion group for this topic? I know it's been discussed, and recently too.
To answer, the biggest justification I know of, for repeatedly sloped teeing grounds, is drainage.
On the older courses, the ridgeline uneveness, that allows the golfer to decide whether he wants a downhill or uphill lie, are my personal favorites. Maybe it's because so many of today's golfers bitch about them, but really that's just an added bonus. What makes them, for me, is that thay allow me to counter-act all the imperfections in my swing, to the point where I can actually hit the shot I imagined, conceived and hopefully executed.