The establishment of this new Institute and the unnamed source (wasn't it Cardinal Ricard, by the way? I seem to remember that.) stating that the Holy Father wishes to establish the Traditional Missal as variation of the Roman Missal, can be interpreted in many ways, I guess.
The way I see it, considering the obligation we have as Catholics to do our best to interpret things in a positive way, this means:
1. There is a good solution to the "problem" concerning the SSPX in the horizon. Note that the decree of erection mentions that it is permissible(not only that, but actually encouraged) to critique VaticanII if done in a "constructive and legitimate way". Virtually every scholarly critique of VII falls in this category, i.e correcting "possible errors" and "reinterpreting ambiguity"
2. The priests of the Institute says the TLM exclusively. No chance of a "time bomb" like protocol1411, since it is explicitly mentioned in the statutes.
3. The TLM is now, according to the Holy Father, a mere variation of the Roman Missal. (Note that it doesn't say the Normative Missal) And which Bishop has the authority to deny a priest in good standing to follow the Roman Missal when he says his Mass? If I look at it extremely positively, I am allmost lead to believe that Quo Primum is reinvoked from the Vatican...
4. This was not done for priests who wanted to leave the SSPX, but for priests who had already left, for various reasons. Laguerie et al did not leave or get expelled for doctrinal reasons, nor because they view VII favourably and suddenly turned Novus Ordo. Essentially, they hold the same views in that regard as do most SSPX priests.
In short, maybe this is the first sign of good will that Bishop Fellay has asked for?
This is the text of the decree of erection of the new Institute from Father Aulagnier's website:
Not much new here but it should be noted that yesterday there was an undocumented comment by unnamed “Vatican sources” to the effect that “the Holy Father wishes to establish that the Traditional Missal is not a separate missal, but as a mere variation of the Roman Rite.” The following paragraph seems to negate this rumour:
« Enfin, aux membres de cet Institut, elle confère le droit de célébrer la liturgie sacrée, en utilisant, et vraiment comme leur rite propre, les livres liturgiques en vigueur en 1962, à savoir le missel romain, le rituel romain et le pontifical romain pour conférer les ordres, et aussi le droit de réciter l’office divin selon le bréviaire romain édité la même année. »
“Finally, to the members of this Institute (the Commission) confers the right to celebrate the sacred liturgy using, and truly as their own rite, the liturgical books in force in 1962, namely the Roman Missal, the Roman Ritual, and the Roman Pontifical for conferring Orders, as well as the right to recite the Divine Office according to the Roman Breviary published the same year.” (Emphasis mine - Mornac).