Matt and Jenna are great, but that is the problem, Matt is more interesting than his Doctor.
As for the mini episode, there is nothing I hate more than when a previous heroic character goes "dark" and spends a few episodes (or season) not saving people, they may claim its for a bigger reason, but its boring.
As for the mini episode, there is nothing I hate more than when a previous heroic character goes "dark" and spends a few episodes (or season) not saving people, they may claim its for a bigger reason, but its boring.