The demands of the original closure (The Valley nine's home hole) are much greater and therefore, imo, a better finisher. Maybe because the natural River is the test? but, I feel it's both the demands to hit that perfect drive, to that narrow fairway, and then the perfect approach over the River, that makes it a better finisher. I'll add that the holes leading up to the original finish, are also, a big part of why I feel the original routing was like the Mona Lisa of GCA, for me. The weakness of the par 3, (after Under der Linden) is also a part of the ebb and flow of the original routing, which screams mid round versus finish. "Mercy" the penultimate Par 3 is also a much better hole than the original and current 4th.
I'm not saying the ninth (current River home hole)is a bad hole either. I just see the course crescendo having more impact, with the Valley nine as the closer.