The users of Google's GWT discussion boards are presumably all rather advanced pros and often don't respond to naive questions about GWT. Would you consider adding GWT to your GUI forum, so newbie GWT users can enjoy the same helpful, gentle aid with GWT they receive with everything else on Javaranch?
I could be okay with creating a forum for something like that if I could get some sort of idea that the forum wouldn't shrivel and die. The shrivel and die thing is the key.
There are lots of things that we could do.
One thing is that if there are several books out there on the topic, we can promote those books in the forum. That will increase traffic. Another is that if we have a half dozen passionate users, they will generally keep a forum rolling along well.
I'm grateful that you told us about how the other forums are not as helpful to newbies as they could be. That does tell me that this could be a good idea. If we created this forum and once a week YOU posted to newbie threads to say "this forum is great for advanced users, but you might find your newbie questions get answered faster at coderanch.com" - that would probably also help a lot.
So what I want to make clear here is: it is possible. I suppose the next step is that there would need to be one person that would pester us a bit in that direction until we either create the forum or we holler "stop pestering us." Oh yeah, and it would need one of the staff to step up and say they would moderate the forum (that staff member doesn't need to know diddly about the subject matter - just has to feel like checking in and watching the fledgling forum).