The biggest weakness's to 2 factor auth are:

1: You can remove 2 factor auth without having to enter the auth code. So if your computer gets a virus, someone can just remove 2 factor auth via your browser

2: The "app specific passwords" are full on backdoors. If one of your app specific passwords gets hijacked, someone can login to your gmail with it and then remove the 2 factor auth pass (See above)

* http://productforums.google.com/forum/#!category-topic/mobil...