I worry about 'Glee.'

Seems like I shouldn't, right? The show, which is returning to Fox after a four-month break on April 13, seems to have everything going its way right now. The show's return is being slotted after 'American Idol.' The kids from the show have been singing and dancing on tour. The mid-season premiere is being screened in movie theaters for charity. The producers are combing the country to find a new cast member (starting today), and the search will become a show of its own.

"Gleeks" all over the country are clutching their soundtrack CDs and season one part one DVDs -- signed by the cast during one of their mall tours, no doubt -- and just waiting for the show to come back. Madonna has given the producers permission to create a Madge-themed episode. Heck, even Neil Patrick Harris is on board to guest.

Hear that? It's the hype machine going into overdrive. And that's what worries me. I've heard this machine before, and it never ends well. There are three signs that make me wonder if 'Glee' is more flash-in-the-pan than legitimate long-running hit:

1. They're already adding new cast members. Yes, I know that the show has spots where new cast members can be inserted. We're going to see the mythical supergroup Vocal Adrenaline in the second half of the season, for instance. And, because the setting is in high school, it's inevitable that new students are going to be in the mix as time goes along; heck, some of the key players in the group are already high school seniors.

But this is a dangerous game; there's a chemistry that has been set up during the first thirteen episodes, and it seems risky to mess with it. As much as it seems like the show's been on for five years -- the hype machine has been that strong -- 'Glee' is still in its first season, and there's still a risk that the long break is going to cause audience erosion. Being sure that the dynamic the show established in its first half season remains will help keep the audience around. Why not at least finish the first season before messing with the formula?

2. The young stars are feeling their stardom - perhaps too much. I've been hearing rumblings from my fellow reporters and critics that the kids from the cast have been tough to deal with. Indeed, during the January press tour, the young stars of the show clustered together during the FOX all-star party and made it tough for reporters to get in to do quick interviews. Oh, sure, some of them were nice enough to talk to us, but let's just say some were nicer than others. The most accessible cast member? Jane Lynch, who's a pro's pro.

I've also had my difficulties trying to get some of the stars to do interviews. For instance, I was assigned to do a story for a local publication about one of the stars, who grew up in the area. After a lot of back and forth, that's person's publicists eventually told me that the actor was too busy to do a ten-minute phone interview with me for what was supposed to be a 300-word piece.

Not that I'm complaining; no actor should be obligated to talk to any reporter if he or she doesn't want to. And, between the tours and personal appearances, the cast is extremely busy. But, you'd think the show would still be in the mode of trying to get any kind of publicity it could get, and it seems like the cast is too young to be giving reporters the brush-off like that. At what point will that attitude spill over into how they deal with the show's legion of fans? Maybe it has already.

3. The show can only get more ridiculous from here. Many shows that have had this kind of early hype -- from 'Twin Peaks' to 'Ally McBeal' to 'Grey's Anatomy' to 'Lost' to 'Heroes' -- inevitably try to make every episode an event by writing increasingly broad stories. The problem is, the show's tethers to reality start to break away after awhile. Think of the LVAD-cutting plot on 'Grey's' or some of the silliness of 'Lost's' middle seasons, or pretty much all of 'Heroes'' run since its first season ended.

'Glee' is already a pretty broadly-written show as it is. In thirteen episodes, we've seen a fake pregnancy, a near-sham marriage, slushie fights, a football team dance the 'Single Ladies' dance during a game, the show choir bouncing on stacks of mattresses for a commercial, and more more love triangles than you can shake a baton at. How silly is the show going to be in season two? How 'bout season five? Exactly. There's going to be a point where even loyal Gleeks are going to roll their eyes one too many times and turn on something else.

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Maybe Ryan Murphy can keep the show from spinning out of control and losing whatever grounding it currently has. But he couldn't keep 'Nip/Tuck,' which had a much smaller audience, from becoming a parody of itself, so I'm not confident he'll be able to keep this from happening with 'Glee.'

So, what do you folks think? Is 'Glee' going to have the staying power for a long run or is it going to flame out quickly?