Traditioni denique fideliter obsequens, Sacrosanctum Concilium declarat Sanctam Matrem Ecclesiam omnes Ritus legitime agnitos aequo iure atque honore habere, eosque in posterum servari et omnimode foveri velle, atque optat ut, ubi opus sit, caute ex integro ad mentem sanae traditionis recognoscantur et novo vigore, pro hodiernis adiunctis et necessitatibus, donentur.
Vatican website translation:
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.
Slavishly literal translation:
Finally, faithfully observing tradition, the Sacred Council declares that Holy Mother Church holds all lawfully acknowledged Rites of equal right and honor, that it wishes to preserve them into the future and to promote them in every way, and that it desires that, when it should be done, they should be revised with careful integrity to the understanding of sound tradition and given new vigor for the circumstances and needs of today.
Following on article 3, this article declares that all presently recognized Catholic Rites share a fundamental equality of honor, that they are also to be cherished/promoted/fostered as the Roman Rite, and that, if these Rites are to be renovated, such renovation should be done in the light of (their own) authentic tradition in order to engage contemporary worshipers.
First, note that the original draft referred to all Rites “vigentes” (lawfully in use), but that this was changed to “agnitos” (lawfully acknowledged) in order to hold open the possibility of the development of new Rites. Second, the Council explicitly rejects an opinion that the Rite used by the Roman church, whose bishop enjoys universal primacy, was likewise preeminent among the other Catholic Rites; practically, this had led to quite a few attempts to “Latinize” some of the Oriental Rites. Finally, it is up to the appropriate leadership of the Eastern Rites themselves to determine whether and to what extent their Rites need renovation in the light of the principles articulated by the Constitution on the Sacred Liturgy.
I am somewhat familiar with the post-Vatican II renovation of the Maronite Rite (proper to dioceses of Lebanon and Lebanese communities) that has attempted to remove some of the Latinizing accretions to their liturgy and restore their liturgical patrimony. I hope that members of the Pray, Tell blog would inform us of where such renovation might be in the case of other Eastern Catholic Rites and what the reactions to such renovation has been over the last fifty years.