I've been watching this threat with great interest and must admit that I am very suspect of DL's intentions with these changes.
While the regional and global upgrades sound appealing, if the availability of low-mileage award tickets is any indication, we'll never get to use these. Personally, I will not be selecting these as my Diamond benefit until I see how this plays out.
As for the no complimentary UGs on the BE transcons out of JFK I think they are making a huge mistake. By not offering these they have eliminated any reason for the most elite flyer to remain loyal to DL. If AA/US offers I would jump ship in a heartbeat.
DL's strategy of late has been perplexing to me.