The recent not upgrade/downgrade statement seems crazy unless they are deliberately trying to cause a lot of 'breakage'
For me the fairest and most simple solution is for MPG to say you had a TP for XX points per night in the old program, and that is worth the same in the new program with the option to upgrade/downgrade as desired (at the new rates)
Either way we will know shortly
That is not totally fair either because many properties, are going way up in points pricing (such as Domes Of Elounda going up from 45K to 85K and Marriott Hawaii Resorts going up from 40K to 50K) merely due to the category remapping or reshuffle and not due to increased demand, cash rates or renovations/upgrades in the property as it is usually case for category increases.
But at least the the increase in pricing was given with 1.5 month advance notice.