Sacrosanctum Concilium 4
The introduction ends with this short paragraph, which first acknowledges various rites:
Lastly, in faithful obedience to tradition, the sacred Council declares that holy Mother Church holds all lawfully acknowledged rites to be of equal right and dignity; that she wishes to preserve them in the future and to foster them in every way. The Council also desires that, where necessary, the rites be revised carefully in the light of sound tradition, and that they be given new vigor to meet the circumstances and needs of modern times.
The point of interpretation for traditionalists would be, I imagine, the necessity of large-scale liturgical reform. In addition to revision, the bishops also called for vigor. Keeping in mind the focus on evangelization and Christian unity mentioned in section 1, perhaps it's not surprising or inappropriate to suggest that Roman Catholic worship lost something of its parochial distinctiveness. What I mean is: Is the so-called similarity to Protestant worship at odds with what is called for here?