Everything you've said here I generally agree with, but I think you wrote this prior to my last comment, so just to note as per my last comment, the reason I favored this over the 3.5 day delay method is ability to respond quicker to a price pump. But there is definitely the tradeoff that you mention in your first paragraph with the worst-case price in last hour term.
RE: Proposed hardfork change to stabilize Hive Dollar’s tracking of USD value