I know it's very very very wrong to mess with plugin code. Especially in a public forum. I hope no one gets angry at me for suggesting a hack of someone else's code but this is what I did to turn on twitter cards on my home page:
/wp-content/plugins/wordpress-seo/frontend/class-twitter.php line 36
CHANGE: if ( !is_singular() )
TO: if ( !is_singular() && !is_front_page() && !is_home() )
This is unofficial and should only be used in version 1.4.6 of the plugin. 1.4.7 removes descriptions from pages due to switch to using $this->options instead of $options = options = get_wpseo_options().
That should solve your problems till .8 comes out.
I hear he no longer monitors these pages so I think I should be safe. That's a real pity. These forums would provide more help to make a better plugin than hosting your own help desk. On top of that you can receive input from other plugin developers. You can't do that if you host your own help desk. I think he has become to over confident in his plugin. Without auto keyword generation this plugins is just waiting to be overcome by another.
Why Yoast! Why!