First of all, it cannot be just be a celebration of theological diversity, many-paths-one-mountain, everybody-on-their-own-journey, or a list of all the possible brands. Sorry, that's just the way the world is, and it is good that UU's recognize that. It's a good thing, but it is not enough.
Secondly, a UU theology has to make a thoughtful analysis of historic Unitarianism and Universalism as liberal Protestant Christian theological tendencies. What was the essence of their divergence from the Christian mainstream, not just in terms of doctrinal content, but in terms of who they represented. Both were born in the early, and idealistic, days of the American Republic. How was their Christianity a Christianity of their times? It's not enough to note our social prominence in the past, or lift up only the Boston Unitarians commitment to ministerial freedom to be doctrinally vague. What are the reflections of the rise of democratic republicanism in what U's and U's preached and thought.
Thirdly, a UU theology has to offer a thoughtful analysis of how that classic Protestant Unitarian
and Universalist broadened and broke down. How was it challenged by the 19th Century colonialism, and global trade? The 19th century saw the first "death of God' and the beginnings of a religious Humanist movement. It is not enough to say that Unitarianism and Universalism "outgrew" or "rejected" or "graduated from" its Protestantism. Just as important as the ruptures were the continuities. My own belief is that while the Unitarians and Universalists bridged the divide between theists and humanists on an organizational level, they were unsuccessful in articulating a theology that was both theistic and humanist at the same time. We are still in the same place in some ways. That some of us believe in God and some don't doesn't seem to matter at all, except when we try to talk about theology.
Fourth, a UU theology has to account for the rise of secularism, and put forward a positive understanding of the role of the church and organized religion in a secularizing society. Are we fine woodworkers in an IKEA world? Are we social directors, creating communities where none exist? Are we the moral consciences of the society? What are we doing, and why? And how does our present role flow out of our history and our thinking?
Fifth, a UU theology has to offer a deep analysis of our current social location and the paths out of our isolation. What do we do and think that we also share with others who are different than us? It is our essence, our core beliefs and practices, that might be share-able and so a UU theology has to identify those things. If Unitarian Universalism can be practiced in a wider variety of cultural settings, what defines that Unitarian Universalism? We are isolated because we tend to think that everybody is actually like us -- we exaggerate surface differences because we underestimate real differences. The step forward for us is to better understand our specific ways and history, to get objective about how we are unique.
Sixth, a UU theology has to explain who are in our congregations and why they are there. I would say that majority of people in our congregations are not there because of our theology. They have other good reasons for being there. They may have another theological perspective altogether which may, or may not, be consciously integrated with UU history, thinking and practice. They may just like the music, or that they feel welcome there. A UU theology does not have to reflect the thinking of every person who goes to a UU Church, but it should be able to explain why people of differing theologies (and different commitments to theology) worship together.
UU's need more theological discussion to move forward. Yet, our discussions are festivals of umbrage which degenerate into phony diversity. The speed with which we go from "You can't say that because it makes me feel excluded" to "Everybody can think whatever they like" to "Let's not talk about theology at all." is pretty remarkable.