Karl Popper argued that simple theories are preferable "because their empirical content is greater; and because they are better testable."
Would the same be true of user interface?
I'm not a fan of either WYSIWYG editors or visual GUI development environments such as visual basic. In both cases there is a danger of narcissism where the developer is overly concerned with the interface they interact with at the expense of the interface they are creating for somebody else. From my experience this usually means that the next person to interact with the code suffers - whether that is another programmer or a user.
Perhaps for some people a visual development environment does not get in the way in the manner I describe. For my own part though, I still spend most of my development time switching only between a text editor and the actual UI that I'm creating.