Re: Bishop's Role in Motu Proprio
The MP isn't about Latin.
Latin is the language of our Rite, and Paul VI asked that every parish be able to sing the Ordinary in Latin, and Vatican II asked that Latin remain the norm, and the vernacular the (indultary) exception to the rule...not an equal substitute.
"All in Latin" and "all in the vernacular" are not equally acceptable substitutes. "All in the vernacular" was not envisioned by the Council, or Paul VI.