The traditional way of designing a css based site is to position the content in a graphic file, the cut it up and create a stylesheet to position the various parts.

It would be great if XWD could be used to create named areas on the page and export to a html page with a separate stylesheet defining each of the named areas.

i.e. it would be like Dreamweaver but with a much stronger graphical component. To do this in Dreamweaver needs additional graphic tools linked in, but XWD is close to providing this functionality now. Perhaps it could be a separate setting for XWD - say, "design in Outline mode"

At present XWD is pitched at "Mum and Dad", or personal, web designers, having the ability to design divs with an external stylesheet would open it up to all the professional designers and developers. It's a similar concept to the suggestion for Wordpress template designer, this technique could be used for all cms template developers.

If you wanted to get real fancy you could include a css editor