I think this was as much a byproduct of being in the Denver Convention Center, which is wired for HD for the Democratic Convention, and next week WNT will be in St. Paul for the Republican Convention, which will also be wired for HD, so I think the true judge of the success of the HD transition will be when WNT returns to the studio ...
(If you recall, the State of the Union was in HD on ABC in January, even though WNT was not yet HD. The reason was that the network pool from the Capitol was in HD!)