Maybe I voice this opinion a bit late in the cycle, but ....
A bit late is one way to put it. All these topics and more were discussed to death a year ago when the payment protocol was first being designed. Bluntly, I think we're all sick of it. You are welcome to PGP sign your payment requests if you want to. If not, then please see my FAQ for discussion:
tl;dr - the right way to tackle governments getting bogus certs issued is certificate transparency. All other suggestions tend to boil down to "here's some handwaving that doesn't actually solve the problem".
By the way, the evidence from the Snowden case rather reinforces the strength of the CA system. Did we see stories about bulk usage of fake certificates? No. What we read is that the increased usage of SSL was a major game-changer for intelligence agencies. They "solve" SSL by compiling databases of private keys they obtain in various ways. True to form when the FBI wanted access to LavaBit, they tried to obtain his private keys rather than just push a convenient "give me a fake cert" button, and when it became known that Lavabit had to hand over their key, GoDaddy revoked their certificate. Industry policies forced their hand and those policies don't have a get-out clause for the FBI.
It's without a doubt that there are government-issued fake certs floating about, somewhere, just due to the scale of hacking that's been taking place. However, demanding perfection in a system that handles security for over a billion people and tens of millions of operators is unreasonable. All we can ask for is that it it's being improved, which through initiatives like cert transparency, it is.
Please, let's call time on these discussions. They long ago ceased to have any value.