I started noticing the length issue a few weeks ago myself.
Especially just in the last few months, the bulk of the (non-Flash) stories seem to be averaging around an hour. In fact, looking back, the pattern started around episode 200. Before that, there were certainly long stories, but from then to 217, as Dave pointed out, there were only three 'regular-length' ones. (The most recent two episodes, at 40 and 45 minutes, I would consider within 'normal-length' range, especially for Podcastle, though the latter is on the borderline.)
Some of the long stories really didn't feel all that long, once I got into them (e.g. "Buried Eyes"), but with some of them I found myself checking my MP3 player in a mental version of "Are we almost there yet?" I appreciate that you and Anna like the long stories - I don't blame you, many of them are very good, but I'm pretty sure that impatience to get the story over with is not the effect you're going for.
Looking over last year's list, I see a smaller preponderance of the hour-or-longer stories, though I do notice they get more frequent later in the year. I guess you've used up all the good, shorter fantasy.