Excellent question; I have dropped both "Alcatraz" and "Person of Interest" after a couple of episodes because of this problem.
Three hypothesis: a) The procedural formula is easier to pull off successfully with limited writing talent. b) Having a handful of permanent characters and the rest be one-offs is cheaper in terms of casting than a complex plot with many, layered recurring characters. c) We are atypical, and most people prefer the comforting, predictable procedural formula. (In particular, it allows for tuning in and out of a show missing episodes here and there with no great loss.)
This is the monthly thread for posting media of various types that you've found that you enjoy. I find that exposure to LW ideas makes me less likely to enjoy some entertainment media that is otherwise quite popular, and finding media recommended by LWers is a good way to mitigate this. Post what you're reading, listening to, watching, and your opinion of it. Post recommendations to blogs. Post whatever media you feel like discussing! To see previous recommendations, check out the older threads.
Rules: