So loyal Diamonds who already have the card get nothing, but those with trial Diamond status were solicited for what would be, in essence, lifetime Diamond status for $75/yr? I see a bit of a PR debacle for Hyatt coming up

I don't believe in the predictions of 'PR Debacles' anymore. How often have we thought some GP decisions would end up in bad press for Hyatt.
Remember that United Airlines Miles promo where some members got a surprise gift of a huge chunk of UA Miles. Everybody was outraged. What happened? Nothing.
For the record, I don't like this situation at all. But as a non U.S. resident or citizen there is nothing I can do about it. I stopped caring too much about my Hyatt Status though. If I keep Diamond past 2015 good, if not it's not the end of the world. Life goes on.
There will always be a shuffle between the big chains when it comes to new customers. People always think the grass is greener on the other side of the fence. In the end it all balances itself. Why do you think do Hyatt and SPG work together when it comes to status matches? Because they know there is no real damage involved but they protect each other against 'Photoshop Elites'.