OP - what exactly are you looking for besides a spot to rant?
Yes, the ticket was expensive. Also, why was your wife firm in NOT paying the change fee? She was changing the ticket without status, and the fee is due. Doesn't matter if DL "resells" the seat or not.
My guess is likely her entitled attitude came across to the phone agents, and they did whatever they could so she didn't pay anything extra and to get her off the phone as quickly as possible. As a Diamond I don't expect any change fees to be automatically waived for me even! (Awards 72 hours out from departure aside)
In the future: exercise some patience and kindness with the phone agents. And stay on the phone with a reissuing agent until you receive and have opened the email receipt and have verified the changes.