Ran into this last week and was a bit frustrated by the change. I have one org that's PDL and the subscription management process, with each device being on its own term, is preferable.
Have another customer that's basically "15 businesses in a trenchcoat" who would have benefited greatly from being PDL and had their renewal coming up, so I went to convert them, only to discover that the option no longer existed.
Some of their licenses are less than 6 months old (MR) and they balked at the price of renewing the entire org and the idea that they had to, given that some of the licenses were purchased quite recently. The argument was that they should only have to renew the devices with expiring licenses, which were for specific sub companies, and these could be billed as such (to each sub company), which I really couldn't argue with. I'd have converted them to PDR earlier if I had known it was going away, but apparently I missed this memo, which is my fault.