Anyone who knows me knows I'm not a fan of canned adventures since they're railroads by definition.
There's a thin red line between a railroad and a theme park: A theme park is a railroad that's actually enjoyable.
If you ask me, there's just one requisite for a successful theme park:
(I was thinking of "Keep It Simple, Stupid," but KISS also makes everything better)
A module is, first and foremost, a scenario:
Definition of scenario
plural scenariosAs a scenario, even the most flexible modules will offer you at most one out of two choices at specific moments in time (which is inevitable since writers can't account for all possible player actions). So, the best modules are those built around circumstances that:
1a : an outline or synopsis of a play; especially : a plot outline used by actors of the commedia dell'arte: the libretto of an opera
3: a sequence of events especially when imagined; especially : an account or synopsis of a possible course of action or events
- his scenario for a settlement envisages … reunification
- —Selig Harrison
1) Are so simple that changes are irrelevant.
2) Are inherently fun, so the players have no need to want things any differently.
Just keep things simple and fun. Just like GMs use modules when they don't feel like writing their own material, players are likewise entitled to put their brains in neutral and go with the flow.
Now, while "modules with rich stories and intricate plots" sound pretty on paper... the thing with rich stories is that you run the risk of players actually wanting in on said stories, and interacting with them... and your module's scenario happens to be written in stone, and 9 out of 10 GMs will stick to the script*, so the more complex the plot, the more it will look like a Second Order Idiot Plot from the outside (see Rise of the Runelords) and the more players will resent being railroaded.
((Boots, right before mysteriously contracting a case of lead poisoning))
So, say with me:
"I'm not the next JRR Tolkien."
"I'm not the next GRR Martin."
"I'm not the next Ryo Mizuno."
A module with such a simple premise as "the player characters wake up inside a labyrinth, don't ask why." is perfectly valid: The player characters are already there, it could be for any reason (it could be a dream for all we know), no motivations are needed, and there's no "story" the players can "disrupt" (also it used to work for Robert E. Howard, Conan used to start each tale in a different place under different circumstances with no explanations given).
Never underestimate the simple little things.
* P.D: Yeah, I know there are those few and proud unicorns who upon reading a module, they de-compile it in their heads and turn it into a sandbox where players can do anything with the story. In case you're one of them, congratulations, but you happen to be the exception, not the norm, and never having experienced a problem yourself doesn't make that problem inexistent to the rest of the world.