Too early for optimism.

I respect Jeff Culbreath and his analytical abilities, but I don't see where he's right that communion for the civilly-divorced and remarried is off the table.

The Instrumentum itself merely describes a multitude of responses without passing judgment on any of them:

Concerning the Reception of the Sacraments

93. In the matter of access to the sacraments, the responses describe various reactions among the faithful who are divorced and remarried. In Europe (and also in some countries in Latin America and Asia) the prevailing tendency among some of the clergy is to resolve the issue by simply complying with the request for access to the sacraments. Other members of the clergy, particularly in Europe and Latin America, respond to the matter in a variety of ways. At times, the faithful distance themselves from the Church or go to other Christian denominations. In some countries of Europe and some countries on the other continents, this solution is not sufficient for many people; they wish to be publically readmitted to the Church. The problem is not so much not being able to receive Communion but that the Church publically does not permit them to receive Communion. As a result, these believers then simply refuse to consider themselves in an irregular situation.

94. Some Church members in canonically irregular situations express a desire to be received and guided by the Church, especially when they attempt to understand the rationale of the Church’s teaching. These people recognize the possibility of living in their situation, while relying on God’s mercy through the Church. Still others, as indicated in the responses from some Euro-Atlantic episcopal conferences, accept the duty to live in continence (cf. FC, 84).

95. A good number of responses speak of the very many cases, especially in Europe, America and some countries in Africa, where persons clearly ask to receive the Sacraments of Penance and the Eucharist. This happens primarily when their children receive the sacraments. At times, they express a desire to receive Communion to feel “legitimized” by the Church and to eliminate the sense of exclusion or marginalization. In this regard, some recommend considering the practice of some Orthodox Churches, which, in their opinion, opens the way for a second or third marriage of a penitential character. In light of this suggestion, countries having a major number of Orthodox Christians noted that, from their experience, this practice does not reduce the number of divorces. Others request clarification as to whether this solution is based on doctrine or is merely a matter of discipline. 

The Instrumentum notes at the beginning that it is merely a summary of the survey responses, and will guide the discussions. Of itself, it settles nothing--note that it does not condemn the practice of European clergy who give communion upon request. It also explicitly notes that some are seeking to clarify whether the bar against second marriages is merely a matter of discipline. A document addressing marriage that does not so much as mention the term "adultery" would seem to be incomplete by its own terms. 

So, the triumphalist interpretation is contradicted by the document itself. Notably absent are howls of protest from the usual suspects--e.g., the German episcopate--which would have resulted if the working instrument was some kind of game changer. The dog that didn't bark, and all that.

Bottom line: we will still have to wait and see.