I think this is great, but would love for it to go even a step further and show click through rates (CTR) as well. Yes, with this information we will probably be able to figure out the rest of their criteria for positioning, but is this a bad thing? If my bid and CTR are the same as my competitor, yet I am ranking lower, I have a choice of either raising my bid or creating a better, more relevant, landing page. Either way Yahoo wins. If I raise my bid, they make more money, if I create a better landing page, their content improves for the user.
So, I say Yahoo adds competitors CTR and Google follows Yahoo on this one by showing us your Quality Index Score breakdown.