I can agree that the UIBuilder could have more features, what maybe you could be more specific.
You can do quite a lot with the UIBuilder, and I use it probably 99% of the time.
Maybe if you have specifics of things you're trying to do, or figure out, some of us who've used the program for a while could gives some pointers or help
But as far as something like Dreamweaver intensive for a XML ui structure seems a bit overkill to develop /shrug