except that the CA or CA hacker can impersonate you, thus it's still one of the multiple single points of failure
If you want pinning, there are better solutions: http://patrol.psyced.org/
CAs will always be able to MITM you. Like I said: "the notion of CAs is problematic."
There are two caveats:
1) certificate pinning: your browser has a hard-coded list of certificates for all major websites (e.g. Chromium: https://code.google.com/p/chromium/codesearch#chromium/src/n... (scroll down!))
2) there are add-ons (ie Certificate Patrol) that warn you when the certificate changes