James Hibberd on EW had a chat about the renewal with HBO executives Michael Lombardo and Richard Plepler, in which they discuss their happiness with the viewership. They note that its numbers are stronger than True Blood‘s were in its first season, and they predict it’s a “slow build” show that will win over more viewers as more episodes air and they decide that it’s worth watching even if they don’t consider themselves a fan of the genre.
On the other hand, they note that Benioff and Weiss are largely writing this on their own, without help of staff (except the odd free-lanced episode), and they think 10 episodes would be best to keep quality high. Which is, one supposes, an imminently reasonable reason to stick to 10 episodes. But the next season, if we are so lucky (*knock on wood*)? This may be why Benioff and Weiss have suggested that they wouldn’t mind splitting the third book into two seasons.