I cannot understand why, in the third millennium, Latin should be the arbiter for determining translations into other languages. If the theology of the Mass can be explained catechetically in any language, why not compose authentic liturgy using vernacular language from the outset? 

Latin as the authorised original text is simply linguistic imperialism, reflecting the Roman Empire. The endorsement of the use of Latin by the Council of Trent only went so far as to anathemise those who said that Mass should be celebrated only in the vernacular.
Looking back at my 1963 Roman Missal, I see that the translation of consubstantialem was “of one being” not “consubstantial” as per the 2010 version. “Holy and venerable hands” seems a strange way to describe the hands of a 33-year-old carpenter who hauled nets with his friends on the Sea of Galilee.

I wish Archbishop Roche every grace and blessing as he undertakes his task.