Issues with Pope Francis's New Motu Proprio

The obvious problems with the recent opening of the ministries of lector and acolyte to women by Pope Francis has already been the subject of a number of articles, including one that I wrote earlier this week. As I reflect further on the motu proprio Spiritus Domini, I see more and more disturbing implications of this modification to canon law. Those who think "it's not a big deal, it just formalizes what we've already been doing for decades!" greatly underestimate the difference between custom (which can include bad custom) and legal formalization, and more to the point, between substitution (women filling in for certain functions) and institution (women being installed in ministry by episcopal action).