(Creeping out of lurkerdom for this.)
I voted Yes, but that’s not totally accurate. For me, it seems like Glee hasn’t so much jumped the shark as it has finally completed the slow transformation that began after the first batch of episodes. I’ve talked about my view of the show with a couple of fans, and they’ve strongly disagreed; I’ll throw it out for you guys anyway and see what you think.
It seems to me that Glee was conceived as sort of a small-town, musical Seinfeld. The pilot and first batch of episodes seemed to be centered around unlikable but strangely appealing characters who found themselves in absurd situations arising from a parody of the banality and venality of everyday flyover-country life as seen through a cynical eye. (Whew!)
After the first few episodes, things seemed to start softening up. They started trying to develop sympathy for the characters, and they eased up on the bleakness of the environment. Maybe it was because the creators realized they had a smash hit on their hands, maybe it was because of the charisma of the actors, but the show seemed to lose its undercurrent of meanspiritedness. The show started to like its characters, and it decided to give them something closer to a typical teen-drama world instead of an outsized satire of that world.
I could be way, way off base here, but that’s how I see it. In the Glee of today, I can’t see any of the writers conceiving of something like Schue planting a bag of pot in a student’s locker as part of a blackmail scheme. I can’t see them introducing a kiddie-fiddler as a recurring character. They’ve even gone out of their way to humanize Sue, for crying out loud. It seems to me like the transformation of Glee is reflected in the arc of Quinn from a ridiculous cartoon of a manipulative cheerleader to a slightly overcooked representation of a standard sadder-but-wiser girl.