I've mentioned before that I think former liberal Prostestants make the best UUs. They generally don't have that creepy distate/hatred/snottiness about their old faith that new UUs who come from conservative religions have and they don't have the somewhat paradoxical yet equally annoying desire to make UUism like their old faith*.
Liberal Christians get that you don't necessarily expect the UUA to make all sorts of decrees about the way UUism is done because most liberal protestants are used to a fairly congregational structure. They are more likely to get that what spiritual attachment they had to their old faith took time to develop and so they don't get pissy when they've been a member for a brief time and have not begun birthing spiritual inspiration like a sexed-up rabbit.
A couple of ministers who have posted here before have mentioned they have a "transitions from other faiths" support group to help people deal with their anger and other residual emotional stuff and move on. I've also heard really good things about an adult RE Curriculum called "Owning Your Religious Past: The Haunting Church" on the same topic. I don't love the title, but I know people who have taken it have found it helpful.
I'm thinking more churches could use this stuff.
* "I love the freedom of UUism. But I think UUism needs more charismatic ministers who will tell us about our freedom and then tell us what we should do with it." is a rough paraphrase of something I have actually heard somebody say in a UU church in a heavily-Evangelical area.
"I love how UUism doesn't make a bunch of political stands I disagree with like Catholicism did, but what we really need is for them to make some moral stands about political issues that I DO agree with." is also a very common sentiment.