Many, many times I have slammed modules on this blog, and the people that use them. Yet, of course, I understand that most people do not 'use' them ... they steal rooms, notions, maps, monsters, etc. What's more, I'll confess right here and now that I did the same thing for many years.
I do not believe that I ever ran any party I've had through a module start to finish. The closest would have been the Keep on the Borderlands, which I bought along with everyone else back in the very beginning of my playing days. Even then, running the party through as far as they got (long time ago, I don't know when that was, but they never made it past the lower monsters, goblins, orcs and so on, before we got bored and moved onto other things), I had to adjust treasure. Treasure was ridiculous on that thing. You'd kill seven orcs and there'd be a +1 sword, as well as 1,000 g.p. worth of jewelry and gems ... and then the next room would have twice as much. And this was a module associated with the same guy who in the DM's Guide wrote against 'Monty Haul' games.
For those gentle readers who do not remember the 70's, Monty Hall was a sleazy looking game show host for a long running show called "Let's Make a Deal" - also famous for the Monty Hall problem (which, I admit, I still can't make sense of in my head - someday I'll kidnap a mathematician and keep him locked in a cell until he explains it in a way I can understand). The game show was very big for its time, and famous for giving a lot of stuff to people that were, basically, extraordinarily dumb folks who didn't deserve shit. At the time Gygax coined the term, Monty Haul, it would have also incorporated the idea that the party getting all that treasure loot had not earned it.
But I digress.
Suppose we try to break down the module into that which is stolen, and that which can be ignored. Images are always compelling, both for showing the party and also for inspiring the imagination. A particular magic item, or something ornate, as well as a wide host of things that fall under the heading of 'toys' can be used in any personally-created adventure. Traps are good. Puzzles too. The arrangement of rooms, as well as any kind of floorplan, can be used more than once. The motivations behind an NPC's action is good, that can be translated elsewhere. In fact, virtually any element of the module can be stripped and reused, like tearing a building empty of its guts in wire and other metal pieces until all that's left is broken concrete, plasterboard and old wood.
The real wasted part of the module comes down to two things: the railroad, where A must be done before B is found that makes C work, opening the door to D and monster E with treasure F; and the 'mood.' The mood, of course, would be the module's author trying their own distinctive emotional perspective of the tone or attitude that the module is supposed to be run with. The mastubatory part, if the reader will, that the writer really likes, and virtually everyone else ignores.
Now, defined, the word "adventure" is a bold, usually risky undertaking, a hazardous action of uncertain success and outcome. This is something I see being totally and absolutely under the control of the DM. The DM ought to know the world being run, ought to know precisely what sort of adventure that world needs, and ought to be able to invent the adventure that is needed. To keep with the building analogy, the materials that are stolen from the module serve to create a space in which business can be performed - but the actual business itself is not created by the builder, but by the business owner. The builder can take instructions and shape the space for the owner, but the builder shouldn't tell the owner the owner's business.
Trying to incorporate a railroad or mood into a host of source material that is going to be demolished and reworked to suit the owner operator - the DM - is a waste of time. Or more to the point, it is a self-indulgent waste of time, for the module builder that wants you, the buyer, to get really excited about the builder's building, rather than in the actual business that is being run there. Builders have always wanted this. Most of the time, people just don't care. The only reason they ever go to that building is because the place they want to buy from happens to be there. The owner relates to the building, but if the builder was more concern with being showy and impressive than in actually just providing a well-designed, organized space, what the owner thinks of the building is, "I goddamn hate this place, and I look forward to the day when moving is practical."
I have been both building my own buildings and running my own businesses inside them for a long time now, and getting my source material not from other fantasy module creators but from deeper, more compelling sources, like religious studies, fiction of every stripe, modern events, human nature and my own twisted take on virtually everything. If I really need source material, there's always time to investigate into some core works like Camille Paglia's Sexual Personae, Spenser's the Fairy Queen, anything by Shakespeare, Coleridge or Alexander Pope, some great source books I have for general trends in world history, Herodotus, Thucydides, Suetonius and Plutarch, Barbara Walker's great fictional sourcebook, The Woman's Encyclopedia of Myths and Secrets, any encyclopedia, Google Books, the internet and an ordinary newspaper. The idea that ideas are scarce and hard to find is really just evidence of an imagination that needs a kick in the ass. Appendix N? More like, Appendix Life.
I don't want to co-opt the word 'adventure' and use it to describe organized source material. The 'adventure' is the business part, and should be left in the hands of the DM running their own business. I'd prefer to keep my nose out of that. However, there is an issue with all the source material in the world, in that it's really cluttered and scattered, and therefore not particularly cohesive. Cohesion is a process, and one that is worth being paid for. So where I think of creating some kind of source material for a campaign, what I am thinking of is the cohesion of a lot of source material so that it is juxtaposed conveniently for the business' use. The building of the building, with a lot of empty space, good hookups, terrific lighting and convenience to local services, transport and suppliers.
Personally, I'd love to do that sans imagery. I'm not an artist, and that means the choke point for any book containing fantasy/fictional source material is going to be finding an artist that a) has my work ethic; b) has my perspective on how work is first created and THEN sold; and c) is able to produce in any style that's needed. That's not always easy. Artists typically want money up front for work they haven't done yet (often all the money), which only makes them the most annoying unregulated contractors in the universe. At least if I give money up front to the cabinet maker who's going to rebuild my kitchen, I know that someone is looking over the contractor's shoulder, and that licences have been obtained and fees paid. But an artist ... artists don't answer to anyone, they don't respect anyone (unless they're a better artist, in which case they are silently hateful, also), and most really don't believe that there's another knowledge in the world that matches their own special snowflake derived mind-sets.
I can work with musicians, sound techs, printers, designers, actors, costumers, writers, editors, poets and dancers ... but artists are a whole different mind-set.
If the reader tells me that I can produce a book of source material without the need to suck up to an artist, I will be deliriously happy. Unfortunately, that's probably not the case. I have engaged an artist recently to do the front cover, and we get along great ... and I pitched the idea of working on a series of sourcebooks together, but ... I don't have an answer on that. I can't afford to pay up front for 10 or 11 pieces per source books, so I need an artist that is willing to work for the possibility of profit - like every other craftsworker, including myself. We'll just have to see.