This depends more on your route and time of day rather than any kind of trends unless you are comparing the same flight city pair, day of week, and time of day to a previous year, and few people really have that kind of data.
I could easily say that DM is not worth it because even last year I was 7th on the UG once as a PM for the 5:55pm 777 ATL-LAX on a Friday night. Oh, and that was
with an RUC (properly applied... I called and checked) to the flight. Or that I have never had a complimentary upgrade as a DM on a U or V fare on that same flight on a Friday in over 5 years. So that one flight is not an appropriate data point for the entire system. Not too many individual flights are.
Or I could use an example like today. 920am MCO to ATL was 6th on the UG list for 3 seats as a DM on a paid U fare. I did SDC to the 620am flight and was
#1 for 9 seats. 3 hour difference in flight times give a completely opposite opinion on upgrade likelihood for the anecdotal observer.