You have a company that is profitable and is known for developing good technology, but that never had an "engineer mindset" at the top. PG himself tells how their biggest problem is that Yahoo's top management doesn't think about "products", but rather about "properties".
Now - after God-knows-how-many "media" CEOs - you have this insanely capable engineer at the top, whose sole focus is on using the brain power at the company for creating products, instead of pushing ads or competing in "social" anything. If she manages to change the culture at Yahoo, I think they will have a strong comeback - and I'd love to be a part of it.
Actually, I'd love to have Paul Buchheit to chime in. He is the one that probably got closest to her, and might be able to provide some insight as to how much of an impact she can have on Yahoo.