Now that it's been some years since I attended the novus ordo, I trust your judgement on this one.
From what I recall though the novus ordo differed markedly depending on whether the priest was tradition-minded or just another raving liberal.
As far as I'm aware omission of the Leonine prayers from the novus ordo was never mandated by the Vatican.
If they are omitted, it's a shame.
The St. Michael prayer and the three Hail Mary's are just plain not included in the Order of the Mass.
It's not a question of being mandated. Pope Paul VI just never included them in the Novus Ordo.
One of the "rules" is - if there is no rule, it doesn't exist.
Unfortunately, that is only followed in cases of Orthodoxy, not inventions.