Personally, I think that quality network dramas (i.e. "Lost") would benefit significantly from switching to a 13-episode season. Yes, this means less money for the studio, but creatively it would mean significantly less 'filler' episodes, you know, episodes that do not forward the main mythology of the series. More meat, less fluff.
In its waining years, "The X-Files" had far too many 'filler' episodes. I mean, those last three years were all 'filler,' weren't they?
- Is the American TV Season Outmoded? (The AVClub)