Google will miss her, because she developed into one of their public faces (ala Matt Cutts, and Adam Lasnik) that they could keep in the spotlight on a regular basis. Vanessa has done a great job of helping to humanize the search giant for webmasters, and always had a smile on her face, even when she was accosted by a troubled webmaster at every turn at Search Engine Strategies and other industry gatherings.
She leaves Webmaster Central to the newly expanded team, which will carry on the good work in her absence.
I am sure that Vanessa will do well in her new role. She is very smart, and very personable. So a public best of luck to Vanessa!