First thoughts on an Anglican ordinariate
An "apostolic constitution" is the form of document used by the Holy See to make the most significant canonical and disciplinary provisions for the Church. It is not, then, a simple "decree" (1983 CIC 29 etc), say, or an "instruction" (1983 CIC 34).
The establishment of a "personal ordinariate" will be something of an innovation in modern canon law, although this ordinariate is apparently going to be similar to "personal arch/dioceses" such as those used for the military (1983 CIC 368 and ap. con. Spirituali militum), or to personal prelatures (1983 CIC 294-297), with Opus Dei being the only example thereof to date. One wonders, though, why both of these structures were apparently found to be inadequate for the reception of Anglicans, and why a third way was invented? We'll have to see.
In any case, the idea of a "personal ordinariate" is another sign of the (I think) inevitable trend away from purely territorial jurisdictional units in the Roman Church and toward greater use of personal jurisdiction. This trend has been evident in western canon law at least since the late 1960s (see, e.g., 1967 Synod of Bishops, "Principles Guiding the Revision of Canon Law", no. 8) and is reflected in the 1983 Code (e.g., 1983 CIC 372, 518). Provided this shift is pursued in an orderly manner, I think it a step in the right direction for people who are coming to see themselves as less identified with various locales, and more with social groupings. Certainly several other groups in the Church will be watching the Anglican project with an eye to applying innovative structures in their own spheres.
Lastly, it strikes me as a bit odd that CDF is, at present, the lead dicastery in this matter. Provisions for "particular churches" usually come from the Congregation for Bishops (ap. con. Pastor bonus 75-76), not CDF. While theological issues (and there are some here, of course) are better addressed by doctrinal experts in CDF, organizational issues (which are numerous here) seem better left to administrative experts in the Cong. for Bishops. But, I'm sure someone has already thought of that.
I'll keep my eyes open for more on this one. It is, as I say, interesting. +++
AmericanPapist helps contextualize the wider situation here.