Stack Exchange network consists of 176 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.
I started a discussion on Area51 about the UI merging. Please participate with the open mind.
I don't think it would work for the reasons I outline in my answer
Merging with anything else currently out there except UXExchange (a SE1.0 site) is a very bad idea. I still think UI/UX belongs in a forum and not the SE model.
I completely agree with the answers of both @ChrisF and @Aaronaught.