I wonder what would happen if, as a design exercise, a designer were asked to take an existing site and create the 'next generation' of that site. Flat photoshop mocks a flow chart and a sitemap.

Now take those docs to another designer, tell them this design has been around for over a year and is stale, and ask them to make the 'next generation' of the site.

Repeat through several iterations. I wonder if you'd just get different design styles, or if each designer would actually innovate, using the previous designers work as a base?

Sadly, information architects and site designers all too rarely use real metrics of demonstrated usability from existing sites when trying to revamp them. I wonder if in those cases it would be better to skip the trouble of actually building the 2nd and 3rd generation sites, and go right to the 4th, 5th, or 10th?

Of course, the real answer is to use a designer who finds out what the actual problems and successes of the previous design were, but this might make an interesting exercise, ala Photoshop Tennis.