Since the game seems to revolve around MMR now – show it.
When it goes up or down, the game should be able to explain why. Also, a player’s MMR should be posted next their scores.
To expand on that, my suggestion is to increase transparency in general. The issue has been beaten to death, but if you’re going to hang veteran/elite players out to dry, they deserve to at least know/understand how it’s happening
For that matter, show your PvE scaling too, with a display like say:
Mission X (base level 50)
+Y levels from personal scaling
+Z levels from community scaling