I am a Catholic. I have a few thoughts on things that should be done with the Church. I am a layman and have not studied advanced theology. I would not presume to comment on that. I am, however, a lawyer and manager. My comments deal with those subjects.
The Catholic Church will never manage Luther's precept of "the priesthood of all believers." In any religious group with a sacramental orientation, I think you are going to have a separate body of "priests" whose "business" is sacraments. (I'm not sure "higher church" Lutherans reach Luther's goal. The Anglican and Orthodox Traditions also probably don't.)
It may not be that important. In Judaism, for example, certain men (the "Kohanim," patrilineal descents of Aaron, brother of Moses) were consecrated as Priests. Today, more than two thousand years after the destruction of the Second Temple in 70 CE, only Kohanim may give the birkat kohanim on Holy Days in the Ashkanazi Tradition. There are abundant underpinnings for a special and separate role for priests.
However, I think we must acknowledge, if not the "priesthood of all believers," the . . . stewardship . . . of all believers.
In the North American Church, there may have been some logic to a Priest in Boston making all the parish decisions for his congregants back in the 19th Century when the congregation consisted largely of uneducated laborers. That rationale no longer holds (if it ever did) when many of such a Boston congregation in 2013 may hold MBAs and law degrees from Harvard and engineering degrees from MIT. Priests are called to be special custodians of the Sacraments. But the laity have (or should have) a voice in the governance of their parishes and may, as volunteers, be more able than the priests assigned as pastor or parochial vicar to decide how to best replace the HVAC system. They may also, like the Prophets in the Jewish Bible, be able to hold those called to positions of responsibility to doing the right thing. The laity, at least here, are not going back to being unheard, and at least some clergy welcome this.
The Church as a whole needs to open itself to other points of view.
2) Ending the Celibacy Requirement for Diocesan or "Secular" Priests in the Western Rite
This issue is usually seen as one of sexual morality and is bound up in the public perception with the child abuse crisis. However, in my opinion, the celibacy tradition is less an issue of sexual morality, than of a Priesthood that has become unduly cut off from the laity and has become self-referential. As described above, there is a need for, in a predecessor of yours phrase, an Aggorimiento; an opening up of things too long shut off. If all that is visible to the Hierarchy are the interests of the abstract Priesthood and the institutional Church and the Hierarchy itself, rather then the interests of real congregations and real families and victimized children (as well as sick men), we need the Priesthood to be "aired out" in the way John XXIII intended the phrase.
Moreover, making such a change (at least as to Diocesan or "Secular" Priests) is not a theological issue. The current practice is a managerial reform made in the 12th Century in response to observed issues with Priests whose oldest son would take over the Parish through primogeniture, without regard to calling or aptitude, and who might have been more interested in what they could grow in the Rectory land than with growing the faith of the laity,
If we are talking about child molesters, the absence of mature, other-enriching, sexual contact with an adult woman is likely not a cause of the crisis.. But celibacy became a beard for child molesters and having a clergy in the Western Rite that largely did not have things (like family) to give them a larger frame of reference than the rectory or the politics of the chancery did not help to detect or react to the problem. Nor were there people, like spouses or adult children, who were outside the frame who could see the picture. I think Catholicism would benefit from our Priests potentially having the in-sights of the Catholic analog of a Rebbetzin or a "preacher's wife (or husband)."
Making this rule in the Western Church consistent with the rule in the Eastern Rite of the Catholic Church (Maronites, Ukrainian Byzantine Catholic Church, Chaldeans, etc.) where Priest who are not monks may marry before they are ordained to the diaconate, would seem to make sense just from the standpoint of consistency. This is especially true where this is currently the rule applied to Priests "coming over to Rome" from the Orthodox Churches, Lutheranism and, increasingly, the Anglican Communion (often taking their Parishes with them). The number of Priests transitioning form other Churches of the Apostolic Succession is small, but growing. We have seen that this approach is workable within the Western Rite. This would, of course, not affect the religious orders, such as the Carmelites, Benedictines, Franciscans and Jesuits.
Also, per the insight of an old mentor of mine, a DivArty Chaplin, a Lutheran Pastor, Priests should not be forced to marry. He used to say being a pastor and a husband is a form of bigamy. However, this change to celibacy in the Western Rite would encourage the vocations of older, married men (like that Chaplin, a former Infantry Officer and Vietnam combat veteran, ordained in the late 1970s) with families and careers and experience which would also contribute to Priesthood becoming less insular.
3) The Conclusions of Paul VI's Encyclical Humanae Vitae Should Be Reconsidered Based on Science NOT Theology
Aquinas believed that abortion was morally acceptable in the first Trimester because of 13th Century knowledge of Embryology. The teaching differs today, not because the Church's teaching changed, but because we know based on 20th and 21st Century Embryology that every conceptus is genetically distinct from the moment of conception. The moral teachings of the Church are unerring and unchanging. Our knowledge of the natural world where we apply them consistently changes through the application of the scientific method. These are truths that are second nature to you as a chemist and theologian.
Paul VI's1968 Encyclical Humanae Vitae drove a lot of lay people away from the Church or away from compliance with dogma. If the Encyclical is a proper application of theology to the natural world based upon science, that is right and proper, the higher good. If it is not, then that is the most grievous Scandal. The fact that John Rock, a Catholic Biochemist who developed the birth control pill in the 1950s with Gregory Pincus, disagreed that the process involved was "unnatural" and the lack of precision in that term gives me pause. This issue should be carefully re- examined by both theologians and biochemists, The people involved should include both celibate Priests and the laity, BOTH men and women. Doing this in a rigorous, fair and open minded manner would do much to restore the Church's credibility in the US, Canada and Europe.
Well to quote an erstwhile Augustinian Priest by the name of Luther:
"Hier stehe ich und kann nicht anders! Gott helfe mir, Amen!" Fr. Martin Luther