Scripture and Creed
Sikhs reject the idea of creeds. They would say that you can't capture God in one written statement, I'd agree with that. Often Unitarians speak as if being creedless means there is no such thing as shared beliefs. Lots of religions in fact are creedless, possibly most of them. But this doesn't mean that there is no shared theology or scripture, or important shared ideas. You have to have that, you're not a coherent religion without it.
It seems to be what Unitarianism needs is not creed but scripture. It is important for me to affirm revelation is not sealed or limited to one book; and I want to reject the idea that the Bible can ever be authority for us. But we do need something that is foundational and scriptural for us. We don't need to define the edges of that, but we do need to find the centre. It needs to be more than the Bible, but less than everysinglebookintheworld. Since I first started going to going to Unitarian churches I've been continuously disappointed by readings in worship from sociology textbooks, poems about flowers and newspaper articles. I long for scripture. For writing that in some sense can be considered revelation. For me this means the Bible, writing from the Unitarian tradition and scriptures from the other faiths of the world. Stuff that has given spiritual succour to several generations, stuff that has a tradition of interpretation and stuff that can become familiar to us. The only problem is that I am very poorly trained in understanding other religious scriptures. And my education is not helping me in that regard. I use the Qur'an a bit, but have never got around to reading any more scripture. I have read all of the New Testament, but haven't read most of the Hebrew Bible; I've read tiny bits of the Qur'an and nothing of anything else. So for now it's the Bible that I use about 60% of the time for worship, because we need scripture.