As a little bit for background information, the Faenza icon set is one of the most popular third party icon sets on Ubuntu, with it being downloaded 661,689 times from its DeviantArt page alone.
When asked whether the default look and feel of Ubuntu 13.04 will change, Mark Shuttleworth had this to say:
"Yes. We have hired the amazing Matthieu [James], which means we can start the icon project.”Icons won't be the only thing being changed in 13.04. Mark also shared word on plans for Ubuntu to ‘work with a University team’ that are experts in typography, design and iconography’, to lend a ‘rigorous approach’ to the development of Ubuntu’s look. Artistically, he also said that "we have been exploring the full theme story beyond Ambiance/Radiance".
Not sure what that exactly meant, so we'll have to wait and see what happens.