Really, try promoting Unitarianism as Official Church teaching someday, go to the National Council and put that on the voting dockit................
Same goes for any Protestant group, I used the example of the Presbyterian Church and challenging the Westminster Confession , you'll see how open they are real fast. Protestants generally are not as wacky as Stephen and Perry's Fundamentalism, but open to core doctrinal challenges- not close.
I speak from actual in the church experience, my sister was on the National Episcopalian Council, she quit over certain proposals and is now simply goes to a non-denominational 'House Church'.