The once-unpopular can never be too popular.

That theory fuels the actions of Charlie Brown, of all people, in Bert V. Royal’s bawdy, intermittently inspired “Dog Sees God: Confessions of a Teenage Blockhead,” which fast-forwards to the decadent high school years of Chuck and the rest of the “Peanuts” crew. CB, as he’s called here, clings to semi-insider status the way only a former outsider can; as a result, he and those close to him suffer.

The intervening decade or so has not always been kind to the gang: a rabid Snoopy ate Woodstock, CB was grappling with his sexuality, Linus was a stoner, and Marcie and Peppermint Patty … you can probably guess about Marcie and Peppermint Patty. We even hear about some of the B-list characters: “Oh. My. God. Did you see Frieda? Naturally curly hair, my naturally skinny ass!”

“Dog Sees God,” which looks to do for “Peanuts” what “Avenue Q” did for “Sesame Street,” was itself a bit of an outsider in the summer of 2004. That’s when it opened at the New York Fringe Festival with an enormously talented group of unknowns (and without permission from Charles Schulz’s estate). Unfortunately, in adapting it for a larger audience, Mr. Royal appears not to have heeded his own advice.

Just as CB finds himself betraying his principles for the sake of long-coveted peer approval, Mr. Royal has sacrificed the balance between shock value and genuine character development that had made his play so effective. His changes may be a capitulation in the face of commercial pressures, or they may just reflect poor decision-making. Either way, they turn his glammed-up, dumbed-down production into one of the season’s bigger disappointments. Good grief!

While “Dog Sees God” was the single most entertaining show I’ve seen in nine years of Fringe-going, Mr. Royal fit within his often uproarious framework several plausible questions about who these characters were, and how their mythic childhood tics and trials had shaped them for better and for worse. Does it represent emotional progress or backsliding when the Linus manque takes the ashes of his beloved blanket and smokes them? And its ingenious finale – involving CB’s quest to learn whether his beloved beagle had gone to heaven – generated loud sniffles throughout the audience.

Folks took notice, and “Dog Sees God” moved to the cool kids’ table, snagging a few industry awards. Of course, you have to look the part if you want to join the in-crowd. So the original director is out, replaced by “It” helmer Trip Cullman. A little more money has been scraped together for sets and costumes that tread even closer to Schulz’s cartoon world (and for the accompanying copyright lawyers, presumably). And the talented unknowns are gone, replaced by a smattering of semi-talented Hollywood faces.

The cast is divided straight down the middle between regular stage actors and West Coast newcomers, and I suspect most viewers could guess which performers fall into which category. (America Ferrara is an exception, delivering a grounded, reliably disgruntled Sally … er, “CB’s Sister.”) The two biggest names, Eliza Dushku (of “Buffy the Vampire Slayer”) and especially Ian Somerhalder (“Lost”),are simply out of their depth. Kelli Williams’s one-note Valley Girl gloss on Peppermint Patty isn’t far behind.

Luckily, Eddie Kaye Thomas is a deadpan delight as the perpetually indecisive CB, and Logan Marshall-Green breathes impressive depths into Beethoven, the put-upon Schroeder stand-in. Even if their scenes together do skew the drama a bit too far from the ensemble, their dialogue is sharp and psychologically acute, with the hesitations and blurted confessions familiar to any adolescent. Ari Graynor finds that bizarre blend of superiority and unease that made Marcie tick.

There was a time when these messed-up kids, despite all the drugs, three-ways, and curse words, were absolutely recognizable as grown-up versions of the “Peanuts” characters. No more: The audience-friendly raunch has supplanted nearly all of the play’s hard-won insight. Maybe Mr. Cullman knew several of his new cast members weren’t up for the play’s trickier emotions. Or maybe Mr. Royal simply wanted to get as many laughs as possible.

Either way, do you remember that squiggly line Schulz would draw mouths with? That flustered-helpless-bemused-disappointed-irritated wiggle? When I was a child,I always wondered if anyone could actually make their mouth do that. Something tells me I would have found out if I had looked at a mirror upon leaving “Dog Sees God”in its new, diminished state.

111 E. 15th Street, between Irving Place and Park Avenue South, 212-239-6200.