Even so, the GWT creators ended up recognizing the value of presentation markup and introduced the UIBinder system (HTML markup + XML for custom widgets), which arguably made my life a whole lot easier when I was working on a moderate-sized GWT codebase. It's definitely better compared to mucking around with Swing-looking code soup.
GWT-P takes this a step further with completely isolated layers (MVP) so that you can easily make permutations of your app bound to a Tablet, Mobile, and Desktop set of Views very easily. I've been using it a year now and love it.