The best overview and commentary on the Holy Father's motu proprio on the Latin Mass that I've seen so far comes from Fr. Richard C. Hermes, S.J., pastor of the Church of the Immaculate Conception in New Orleans.
Fr. Hermes makes it clear that the Pope didn't "bring back the Latin Mass" because it never went away. It was always permissible to say the Novus Ordo Mass in Latin, and Latin "remains and always has been the normative language of the Roman Rite."
He expresses hope that the more generous permission to say the Tridentine rite will help "restore liturgical balance and can assist the Church in preserving her ancient spiritual riches."