Does the Lectionary Mark a Rupture?

Is there a real divide between the theology expressed the two forms of the Roman Rite? Pope Benedict would have denied it

In many ways there are so many similarities between the two that when both are celebrated in Latin, the language the Second Vatican Council expected Mass to be celebrated (though remember: until Trent the Latin Rite wasn't always in Latin - Greek was used in  Athens which was Latin Rite) and when it is celebrated ad orientem, as the Council and even the Missal of Paul VI expects (which in some Roman churches had never happened because of the Confessio before the altar), apart from prayers at the foot of the altar, which happens before the Mass actually begins, visually there are only slight differences. Not all of us have dancing and balloons at Mass! Indeed it could well be argued, as Paul VI does in the Preface to his Missal that Novus Ordo, is indeed an "organic development".

So what is the major difference? I touched on this in my last post and I think is worth highlighting and asking for comment, I said:

Celebrating the Traditional Mass every Sunday, I can't help being struck by how often the Epistle refers to the evil of "fornication", "adultery" and last Sunday, "sin that should not even be mentioned among you", these extracts seem to be rare in the OF Lectionary, or is that just my lack of attention?

It is not something I have thought of much, and certainly not something I have studied, and really it is only a bothersome thought. Certainly the OF Lectionary gives us a broader selection of readings, including the Old Testament and extracts from the Gospels other than mainly Matthew and chunks of John. In many ways the modern Lectionary is superior, as a logical academic presentation of scripture the older form is obviously inferior.
I don't know quite how the older Lectionary emerged, presumably like most organic forms, by a process of evolution and to meet pastoral needs, it was tried a tested in the crucible of sacred history down the centuries.
What is more significant and worthy of serious discussion is the rupture that I would suggest the newer Lectionary has introduced into the Church's presentation of the image of God. The pre-Concilliar image of God is different from the post-Concilliar image.
Revelation is both Scripture and Tradition, it is within the Liturgy that Revelation is presented: by changing the Lectionary have we broken with something very important?