Hypothesis: the ten-episode season is an artificial construct that will ultimately work to the detriment of Game of Thrones

To put it another way - and note that I can't back any of this up until we actually see Season 4 - I think A Storm of Swords would have been much better served by (say) seven episodes leading up to the Red Wedding, a mid-season break, and then (say) five more episodes in the fall.