Nick, You Overlooked The Same Thing As The Authors
RE http://www.habitablezone.com/space/messages/29719.html
The author's simulations were forward looking and did not address the migration of the hot Jupiters to their current location which is what many other simulators have stated would make Eathlike planets unlikely. My comments are based on press relase reviews not the full article. Please forgive me if I missed something relevent in the full article.
Regards,
Mark