In my view, the only weakness of St. Andrews as a Open Championship course is that if a player stands on the 72nd tee with the lead, the tournament is almost certainly over (barring a Doug Sanders-like event). Don't get me wrong--I absolutely LOVE that hole, but I'd love to see a tougher finish for a major championship.
I think the last hurdle to winning a tournament, especially a major, should be a high one, not a low one. As a spectator, I love it when a guy has the championship within reach, maybe even can see the trophy sitting up there waiting for him, but has to hit some great shots to finish the job. Add a chance for disaster, and that's my perfect tournament finish.
For me, it's Carnoustie.