What happened to the original plan to base Ghost on Wordpress? I love Node as much as the next guy, but surely basing it on Wordpress and therefore PHP would make it much accessible.
Basing this on WordPress is a bad idea. At a certain point to move in a different direction, you can't be shackled to an existing thing just because it's popular.
Another reason to not use a wordpress base, security.
I have never had more compromises with "fully patched" software as with wordpress.