Eric - Thank you for sharing your insightful analysis. I have been chatting with a lady in Florida about AF issues on her D700, and there are multiple complexities there as well. I have cautioned her not to leave all the decisions to the camera, as doing so renders it an extremely expensive point-and-shoot machine and leaves her wondering why things did and didn't work.
I'll restate what an old boss at the US 7th Fleet used to have on a piece of paper taped to the front of his desk. In ballpoint pen, it stated simply: "Too many moving parts..."
Thanks again -- this is the kind of thoughtful examination of our cameras and how they work that marks you and our fellow Nikonians as somewhat of a different kind of photographers. I of course, mean that politely and positively!