I'm not one to quibble about how a successful television series is made. A good show is a soup with lots of ingredients that have no business being in the same pot. Good-looking actors-- but not TOO good-looking. Compelling story arcs-- but interesting episodic writing. Characters who care about each other, but are able to mortally insult each other regularly. If it's a soup, it's Beef-and Bubble-Gum Stew.
I'm not a regular viewer of "Glee" on FOX, but I catch it now and then. As TV show metaphors go, it's more briskety and bubble-gummy than most shows. It's a showcase for a number of audacious gimmicks and marketing strategies. It's skewed young, a demographic the nets still slaver for-- But those kids sing a lot of standards and classic pop, which will allow any 25-and-older-type-person to be able to get their dentures on at least a corner of it. They sell their own versions of these songs on iTunes, which must be a lovely source of non-advertising coin. And each episode is an opportunity for a flimsy theme: It's Britney Spears/Lady Gaga/"Rocky Horror" week! This gives "Glee" a weird critic-proof edge: unlike most shows, they can jump a different shark every week-- and there are, many, many sharks in the sea, my friend.
I've noticed, in my fitful viewing, an interesting shift of characters between Season One and Season Two.
"Glee" was a hit pretty much out of the gate, and it had a true breakout character: Sue Sylvester (Jane Lynch), the vindictive cheerleading coach who tried to derail the Glee Club once a week. Like everything else on "Glee," she skews two ways: as a villain (if you like the Glee kids) or an exasperated agent from our plane of reality (if you're annoyed by the Glee kids).
Breakout characters are a good thing: they indicate the show they came from is becoming part of a larger public discourse. Maynard G. Krebs, Barney Fife, The Fonz: Examples of characters who at some point eclipsed the designated main characters in popularity. This is a great development for the nets and the showrunners, not so much for the writers (who have to give the public more of what they love without breaking the show) and, I'm sure, the actors who played Dobie Gillis, Andy Griffith, and Richie Cunningham.
From what I've seen of "Glee's" Season Two, a new dynamic seems to be taking hold. Sue is still there, generally driving the B storylines as before. But it seems to be that the showrunners have taken great pains to sand off all her true meanness. She seems far less interested in trying to destroy Will Shuester's glee class, and is given all sorts of ongoing character complications (a sister with Down's Syndrome, an estranged mother, etc.) to make her more... I don't know, sensitive? What I do know is Sue Sylvester's tart reposes are so tamed down now her storylines are more distracting than menacing.
The interesting thing I mentioned: I think the showrunners are trying to willfully engineer a new breakout character in Kurt Hummel (Chris Colfer), an openly gay student in the glee club. As Season Two has progressed, his character's arc seems to be taking up a larger and larger part of each episode. The last one I saw had every other character acting fully on his behalf-- even Sue Sylvester.
You can tell who the breakout character of a show is not by watching the show itself, but by looking everywhere else: the Internet, supermarket check-out lines, mentions by your friends on Facebook, etc. If the public's reaction is accurate, the popular characters are still Sue and the nominal leads: Finn (Corey Monteith), Rachel (Lea Michele) and especially Quinn (Dianna Agron). I don't see any particular public buzz for Kurt, no more so than the rest of the ensemble.
Now, I admit I'm a bit awed by Chris Colfer's work on "Glee:" He's playing the part, if you pardon the expression, absolutely straight. From interviews I've seen, there is not a lot of difference between him and his character. The amazing part is his success with the sort of screen persona every aspiring gay actor since talkies were invented, due to the prejudices of the day, had to take great pains to hide. Be it luck or the times we live in, Kurt is an undiluted version of the majority of guys I knew from high school Theater Arts.
Which brings me back to why, exactly, Kurt is taking center stage in Season two. I'll guess it's because of a simple reason: his story is the one the producers want to tell. Which is why "Glee" is beginning to feel like someone rewriting their own high school experiences-- from a very particular perspective.