It's not just the use of the vernacular that's being objected to, the whole mass was changed. However if you are interested to know the benefits of retaining Latin, here you go:
I agree that most of the rituals from Pre-Vatican II (the sequel!) should have been retained, but the ONLY negative of getting rid of the Language of the ROMAN EMPIRE is the lack of a universal lingua franca. As I said, the Church in that case could use Aramaic or English. The latter is unlikely due to certain Euro-Peons at the Vatican who have a cultural prejudice against "Anglo Saxons."