The way I see it Yahoo is strategically stuck because they put their head in the sand and stopped "radical" innovation about 10 years ago and instead just focussed on doing what they do extremely well. While Apple, Facebook and Google were out there inventing whole new kinds of product Yahoo was just perfecting their existing stuff. Now they are in a tough spot because the world has moved on and they are fast losing end-user value because they don't have any foot holds in new markets.
Personally - I got a Yahoo! Mail account in 1997 and it was my primary "personal" mail account (as in, what I use with friends and family) until last year. Then I got an Android phone, and it blew Yahoo out of my life because the integration of Google services is simply unparalleled on there. This is slowly happening in all kinds of ways, and its not easy to see what the path out is other than to look 5 years ahead and restart the innovation engine and do some totally radical things, as you say.
Yeah, all the products you listed are cool, but they are not worth $19 billion (current YHOO market cap.).
You can have a strategy that doesn't care if people use you as a verb or think of you as a search engine, but you still need to have a strategy. Yahoo! has none.
It is over 2 on Price to tangible Book(I do not really count much goodwill in Yahoo brand), over 20 on P/E.
I am not a pro, so perhaps I am missing something in Yahoo.
I'm also sorry to see David Ko go, he seemed like a really good guy.
But they lack any sort of strategy or vision. Wall Street has assigned $0 to the entire value of Yahoo! as a solitary business unit. They should have sold to MSFT but they didn't and now they need to move on.
What they need is to gut the top, promote from within and act like a startup again with a true leader who is willing to think long-term and galvanize the troops. The people at Yahoo! want leadership, and they want a strategy and they want to succeed. But until they get that from the top, they will continue to leave.
The only thing they have going for them in their favor is that they have lost so much value, that taking a gamble to restart the engine isn't that big of a gamble at all.