Spotted this on r/Delta - who knows if there's any validity behind it, though it certainly wouldn't be surprising to see DL move to a more revenue based program ala AA's Loyalty Points. As someone who hits PM off of long, mostly inexpensive flights, and the MQD waiver, I can't think that any changes would be a good thing for me, but guess we'll just have to see what (if anything) is up.
FWIW, the equivalent of PM on AA (Platinum Pro) is ~$14k in ticket spend assuming you already have the status and spend no money elsewhere in their ecosystem, and UA is $12k and 36 segments or $15k. I hit PM with ~$6k in MQD last year plus the Amex waiver, which probably isn't internally worth 9k to DL.