I think that the change being discussed here is taken out of historical context, in that it is far too rapid.
How much did the Tridentine Mass change between 1570 and 1962? Not a heck of a lot. When we talk about the TLM changing, we can’t think of it in terms of a Novus Ordo time frame. We’re talking about a couple of words being changed and an added or removed gesture every few centuries. The EF will never become the Novus Ordo–and if it does, it will probably take another two thousand years for this to happen.
The OF, however, by its very nature, is subject to much greater change, and it seems to me that in forty years, we could all be attending an EWTN-style Mass in nearly every Diocese in the World. This may not happen, but is certainly possible.
The Tridentine Mass, which was never and will probably never be abrogated, will always stay generally the same. If any of you are familiar with the pre-Trent rites, and have studied any of the rubrics, you will find that the Mass of St. Gregory the Great and the Mass of Bl. John XXIII are very similar. In fact, from the point of view of many of us, who are so used to the huge jump between OF one minute and EF the next, they are virtually the same.
To close, any change that happens to the Mass organically is typically a good thing. We can all agree that the Easter Triduum was a good thing, and any future changes made to the TLM over the next centuries will be of that nature–i.e., in the Spirit of both Trent and Vactican II, under the watchful eye of a good and wise Pontiff like Benedict.