The Silence of Reverence
I don't think the answer, fundamentally, is to put the word 'God' into the principles/purposes/covenant of the American UUA. In the UK, we do have the word 'God' in the General Assembly Object, but this doesn't really make a difference to anything.
The First Source, as currently defined by the UUA, is this:
Direct experience of that transcending mystery and wonder, affirmed in all cultures, which moves us to a renewal of the spirit and an openness to the forces which create and uphold life.
The answer, in my humble opinion, is to take this statement seriously. Whether you say the above or 'direct experience of God' is not the issue. The issue is whether you really do live and worship as if a source of your life and faith is direct experience of ___. Direct experience, not preaching about it, not discussing it, experiencing it. If we actually live our religious lives, individually and collectively, as if our purpose of being is direct experience of religious reality, then we can become the powerful religous community that we need to. It astonishes me that all these years after Emerson we still haven't taken on his central insight: that experience of the universe and its Source fully, freshly, is what matters, not preaching or arguing about the words.
Our worship needs to become centred on praise and prayer, rather than readings and sermons. You can say God as many times as you want in a sermon but I'm only going to experience God directly if you shut the hell up and give me some silence so that I can have some time with God. We can pray together, and one person can say, 'what I experienced was God' and another says 'what I experienced was Oneness with everything' or one person says 'it felt like a Mother' and another says 'it felt like Light' - then we can dialogue with each other about our different languages of reverence. But only after we have shared together the silence of reverence. What is needed is to share together in a spiritual practice that binds us to one another and energises us to change the world. If that happens, then I'm much less bothered about the language myself. I will continue to speak of God, and others may not. But that will matter less and less, and our disagreements will be less painful if we have sat together, directly experiencing that which is beyond naming, that which requires the silence of reverence.