“Doc Meets World” lacks a solid focus, is haphazard in its structure, and skirts too many big issues. But it works anyway, thanks to the charm and intelligence of its three compelling leads.

Yep, I said three. “Boy Meets World” fans likely already know who, from the cast’s Core Four, is absent – because they’re probably among those who made the “Pod Meets World” podcast such a smash success that it’s inspired a national tour, an upcoming book, and this documentary.

Danielle Fishel, who played Topanga in the beloved 1990s sitcom, serves as the solid center of the podcast team, which also includes Will Friedle (who played goofy older brother Eric) and Rider Strong (rebellious but sensitive Shawn).

Which means, of course, that we are missing the Boy himself, Ben Savage (protagonist Cory Matthews). Savage not only declined to participate in the rewatch podcast the others started four years ago, he won’t even return their calls. Why? No one really knows.

Nor do they seem to care all that much, though podcast listeners are aware that this mystery is more painful than the movie lets on. But directors Chris Levitus and Zane Rubin keep the focus away from Savage, to celebrate the subjects and their “Pod Meets World” podcast tour. We mostly follow the trio as they travel the country, goofing around backstage and playing to packed houses. Along the way, each opens up about their experiences as child actors, and also as adults who were once child actors.

All three come across as genuine and committed, to both their own growth and their joint projects. When your life has always been defined by others — parents, producers, fans — it’s not easy to forge an entirely new path. Fishel and Friedle seem to have made peace with this dilemma by finding ways to own it. She appears grounded and sensible, even as she recalls how difficult it was to grow up as a young woman in the public eye. He’s equally honest about his struggles, particularly the intense anxiety that kept him at home and out of sight for years. As for Strong, he seems to be working out his feelings about the show and his childhood as we go; his anger and resentment eventually hint towards a poignant and as-yet-unresolved confusion.

In other words, there is a lot of complex material to be mined here. But Levitus and Rubin, making their documentary feature debuts, don’t quite know how access it. Without a doubt, the tour scenes are fun to watch and the interviews are often moving. But they don’t reach the depths that are just visible beneath the surface.

We see Friedle’s hurt when Savage blocks his texts (!), but the filmmakers are hesitant to dig deeper. We hear that Fishel’s mother pushed her to get right back into acting after the show ended, but we don’t learn much more about their seemingly complex relationship. And Strong is working so hard to refocus his ambitions that one could likely make a fascinating film just about him and his own journey.

What we get, instead, is a companion piece, designed as another element of the “Pod Meets World” franchise. We learn a little more about the podcast, and a lot more about the tour (which seems genuinely delightful). We also meet up with several other cast members briefly, including Matthew Lawrence (Shawn’s half-brother Jack) and William Daniels (Mr. Feeny, as you must know if you’ve made it this far into a review about a “Boy Meets World” documentary).

Ultimately, “Doc Meets World” comes to feel like a masterfully-designed blend of promotion and fan service. Without a doubt, anyone who already loves “Boy Meets World” will walk away equally invested in the podcast.

But a great documentary works for everyone, including those who know nothing about the subject. Fishel, Friedle and Strong are such compelling protagonists that it’s hard not to wish for more. Perhaps someday, these three interesting people — who grew up to become producers, writers, and directors themselves — will give it to us.