This piece of news got some attention Monday morning:
The Vatican reiterated July 20 that Catholic parishes should normally be led by priests, stressing to bishops across the world that arrangements for religious sisters or laypeople to head local parish communities can only be made when there is a shortage of ordained ministers.
In a new instruction meant to guide bishops who are undertaking parish reform efforts, the Congregation for Clergy emphasizes the Catholic Church’s teaching that only a priest serving as a pastor can exercise “the full care of souls.”
Arrangements for non-ordained people to lead parishes can be done only when there is a lack of priests, and “not for reasons of convenience or ambiguous ‘advancement of the laity,'” the congregation states.
Further, it specifies: lay people appointed to such roles are “not directing, coordinating, moderating or governing the Parish.” Those actions, it states, “are the competencies of a priest alone.”
There is one section of the document that is devoted to the role of deacons. Here is the Vatican translation: 
79. Deacons are ordained ministers, incardinated in a diocese or in other ecclesial realities that have the faculty; they are collaborators of the Bishop and priests in the only evangelizing mission with the specific task, by virtue of the sacrament received, to “serve the people of God in the diakonia of the liturgy, of the word and of charity.”
80. In order to safeguard the identity of the deacons, in view of the promotion of their ministry, Pope Francis first warned against certain risks relating to the understanding of the nature of the diaconate: “We must be careful not to see deacons as half priests and half lay people. […] And the image of the deacon as a kind of intermediary between the faithful and the shepherds is not a good thing either. Neither halfway between priests and lay people, nor halfway between pastors and faithful. And there are two temptations. There is the danger of clericalism: the deacon who is too clerical. […] And the other temptation, functionalism: it is a help that the priest has for this or that.”
Continuing the same discourse, the Holy Father then offered some clarifications regarding the specific role of deacons within the ecclesial community: “The diaconate is a specific vocation, a family vocation that calls for service . […] This word is the key to understanding your charisma. Service as one of the characteristic gifts of God’s people. The deacon is – so to speak – the custodian of service in the Church. Every word must be well measured. You are the custodians of service in the Church: service to the Word, service to the Altar, service to the Poor.”
81. The doctrine on the diaconate has undergone an important evolution over the centuries. His resumption in the Second Vatican Ecumenical Council also coincides with a doctrinal clarification and with an extension of the ministerial action of reference, which does not limit itself to “confine” the diaconate only in the context of charitable service or to reserve it – as established by the Council of Trent – only to the transient and almost exclusively for the liturgical service. Rather, the Second Vatican Council specifies that it is a grade of the sacrament of Holy Orders and, therefore, they “supported by sacramental grace, in the diakonia of the liturgy, of preaching and of charity serve the people of God, in communion with the bishop and his presbytery.”
The post-conciliar reception takes up what has been established by Lumen gentium and defines the office of deacons better as participation, albeit in a different degree, in the sacrament of Holy Orders. In the audience granted to the participants in the International Congress on the Diaconate, Paul VI wanted to reiterate, in fact, that the deacon serves Christian communities “both in the proclamation of the Word of God and in the ministry of the sacraments and in the exercise of charity.“On the other hand, although in the Book of Acts (Acts 6,1-6) it would seem that the seven men chosen are intended only for the service of the canteens, in reality, the Biblical Book itself tells how Stephen and Philip fully carry out the “diakonia of the Word “. Therefore, as collaborators of the Twelve and Paul, they exercise their ministry in two areas: evangelization and charity.
Therefore, many ecclesial offices can be entrusted to a deacon, that is, all those that do not involve full care for souls. The Code of Canon Law, however, determines which offices are reserved for the priest and which can also be entrusted to the lay faithful, while there is no indication of any particular office in which the diaconal ministry can express its specificity.
82. In any case, the history of the diaconate recalls that it was established within the framework of a ministerial vision of the Church and, therefore, as an ordained ministry in the service of the Word and of charity; the latter area also includes the administration of assets. This dual mission of the deacon is then expressed in the liturgical context in which he is called to proclaim the Gospel and to serve the Eucharistic table. Precisely these references could help identify specific tasks for the deacon, enhancing the aspects proper to this vocation in view of promoting the diaconal ministry.
I was struck by this passage:
Many ecclesial offices can be entrusted to a deacon, that is, all those that do not involve full care for souls. The Code of Canon Law, however, determines which offices are reserved for the priest and which can also be entrusted to the lay faithful, while there is no indication of any particular office in which the diaconal ministry can express its specificity.
In other words: “The deacon can do a lot, as long as he’s not a pastor. We’re still figuring it out.”
There is much more. You can read the entire document here.