Well, we all know by now that the decision to take TPiR to an hour was a brilliant move...
But...
What shows don't or didn't work for an hour? This also includes double runs.
The one that comes to my mind first is Pyramid. While we all have our gripes with the show, I certainly don't find it unwatchable. However, UPN Detroit gives an hour at 9 AM (Followed by Feud at 10). I generally find myself tired of the show after a half hour, and flip to something else, or get online at 9:30. Possibly it doesn't help that they're using a lot of country musicians (blech) this week in the second ep, and the games are just turning into a Jeff Foxworthy joke.
However, I can sit and watch an hour of Feud (just the same way I did on CBS back in 1990). Then again, I don't mind Richard Karn, and Feud is one of my all time favorite games.