Generally I'd agree with you. And generally I think these releases are PR. But the sentence in question "feels" more sincere than that to me:
She said it's "important that the page be dynamic, that it feel very fresh, and that it be very intuitive, and that it really tries to embody beautiful design".
In context, I don't think the first word, "dynamic", means AJAX, I think it means conveying energy or excitement. Putting the "Yaa-hoo!!!" back in Yahoo, if you will. The hero images change out. The weather, stocks and scores are up to date. On the iPad, you have an edge to edge (full bleed) hero image and thumbs you can scroll to. On the iPad, it does "feel" dynamic without being annoying.
The next word, "fresh", is the opposite of what Yahoo's been for a decade. The Yahoo look until not long ago still hearkened back to its curated directory days. When visited from an iPad, her new design does feel up to date, without feeling like it came from Bootstrap Template Monster Ville. You can recognize at a glance that this is not MSN, AOL, et. al. (However, when visited on a desktop, I think it feels more like a shuffled iGoogle, so not so fresh.)
There is a risk in "intuitive" in that it's crucial for the Yahoo audience which is a little older and more change averse. In this case, the word needs to mean approachable and immediately grokked by their majority. Grandpa needs to be able to find his scores and grandma her horoscope. I suspect this word used here signals why this page isn't singing and dancing with undiscoverable swipe style affordances.
The "beautiful design" is the hardest to accept, if visiting from the desktop. On the iPad, I was struck how nice it looked. On the desktop, I think she might be bringing too much Google to her aesthetic. "Clean" is not equal to "beautiful", and I'm not even sure it's clean given the use of grey hairlines and shaded boxes to delineate content areas. A more "beautiful" design might, for example, convey the content area boundaries aesthetically, and have the grey hairlines and shading show up only when the gear (settings) and X (close) icons are needed. With a decade of Google behind her, she probably does consider this presentation more "beautiful" than any of the section home pages you reach from this page.
Word by word, I think she used the best words she had on hand for what she was directing her redesign team to come up with. I like that she talked about how it "felt" rather than just metrics.
If you spitball a bunch of terms you want your home page to convey, this isn't a bad list. Perhaps these particular words sound overused because, well, a home page like Yahoo's needs these words as priorities.
I didn't read her comment as insincere or corporate speak or even marketing speak. I think it's honestly what she was going for.