I wrote up some similar points and posted the trimmed down version a moment afterward. I'll reply instead, and try to avoid bashing the design since you've got that covered. Instead I want to discuss focus. Being neck-deep in Startuplandia, I'm accustomed to discussing smaller companies who are striving, struggling even, to achieve success with a singular focus.
Do one thing, do it well. You won't gain users doing several things poorly. Or in Yahoo's case, you will hemorrhage the users you once had.
I understand that large companies do have the resources to delve into many spheres and markets at once. I also grasp how each additional product/focus can leverage your brand recognition and existing userbase for alternative revenue streams. Even if only 10% of my users pay for [New Feature X], that's still money in the bank! At the same time, when I think of Yahoo, three things come to mind: Email, Search and Content (so-called).
The first two aren't anything Yahoo is the name for anymore and the last one is ludicrously expansive. News, fine. Original web series videos, eh, maybe? But look at the first three items on their list. Autos, Dating (?!) and Finance. Yes I know it's alphabetical, but it's a sign that they still think they can be "The Homepage of the Internet" or some such madness.
This may be the point where Yahoo has to get its hands out of some of those cookie jars and focus on doing less, better. Even if that means a shiny, new platform at the expense of current ones, and even if that means it's a little over-hyped. As long as they finally have one thing they can point at and say "THIS is what Yahoo does, because we do it better than anyone."