That would likely work for targeted attacks against browsers other than Chrome (and maybe recent FF, I'm not sure) but not for large scale dragnet attacks.
"In addition in Chromium 13, only a very small subset of CAs have the authority to vouch for Gmail (and the Google Accounts login page). This can protect against recent incidents where a CA has its authority abused, and generally protects against the proliferation of signing authority."
(disclaimer: I work for Chrome but not on these features.)