Izanagi is probably one of the most broken techniques in the Naruto verse and to even stand a chance of countering it you would need a sharingan. I agree that Kakazu was beaten a little to easily given his potential but I still think that Danzo should've won that battle against Sasuke with ease.
Like you said Danzo was fighting like a fool, which I think was a perfect example of PIS. Why would Danzo, who is such an accomplished and experienced ninja, fight the way he did against Sasuke? Ridiculous.
So I'm still going to stick with Danzo in this one.