The Problem with Adventure Paths
"Adventure paths" or serial modules are inherently flawed. GMs need lots of information early, but publishers can't provide it.
I'm talking about multi-part, highly linked modules, published over a long period of time. The modules are highly enough linked that simply running a few portions would feel incomplete and would miss large portions of story. These aren't a new idea. Arguably the classic AD&D Slavers, Giants, and Drow series were adventure paths. The Dragonlance modules absolutely were. This sort of style of module has continued to exist, but has gained a bit more exposure with paths like the Shackled City and the newer Scales of WarThe core problem is that gamemasters customize and tweak pre-written modules. You may rewrite the module to better suit your player's preferences or to better draw the player characters in. You may find parts of the plotting or the challenge that you dislike and correct them. You may tune the pacing or add foreshadowing. You may need to rewrite parts to cope with wildly unexpected player decisions.
All of these things require a view of the big picture. Knowing that, say, there will be a demonic invasion halfway through the campaign may influence your plans. Maybe a PC has a hatred of devils and it's reasonable to switch the invasion from demons to devils. Maybe the PCs set up a defense force that the invaders are aware of and would change their strategy.
You also need details. If an entire section of the campaign is fundamentally built upon a seemingly minor non-player character being a beholder in disguise, you need to know. If you don't, the NPC might die in a relatively trivial attack. Sure, you can rewrite to compensate for his death by making someone else the beholder, but you need to know in advance to ensure that suitable foreshadowing and clues are present.
Now a key part of adventure paths is that they are published before they are complete. This is inherent to the publication model. If the entire path was was written before the first was published it could be published and sold as a single unit. In this way it's like episodic television or a video game. The initial investment is lower. Profits from the earlier episodes can fund development of the later episodes. Content hungry GMs also appreciate getting access sooner.
So here is the conflict: The GM needs details about what happens in the last module before starting the first one. The publisher simply can't provide details. They typically have a general outline, but the details are still in flux!
One option is to wait until the path is complete before starting the path. This means that the the benefits of getting the content earlier are eliminated. If they are buying the content as it is published, the GM is paying for content they have to sit on. There is also an increased risk that the players will stumble across spoilers, reducing some of the fun surprise. However, if the GM is willing to wait it works fine. The have all of the information they need. For example, a friend ran the Shackled City adventure path for us. He didn't start until the path was complete. He modified the module to better draw our characters in. He rewrote parts he felt were weak. He wrote out redundant characters and reused exsting ones, making the story tighter. He added forshadowing that couldn't be added originally because the later details weren't nailed down when earlier modules were published. The game was great!
The other option is to run the game incomplete, hope that the later parts will be good enough, and quickly try to work around problems that crop up in real play. The end result may be plenty of fun, but it won't be as good as it can be.
All of this make it clear why Wizards of the Coast's secrecy policy for the new adventure path is a terrible idea. Randy Buehler wrote, "The problem is that we’ve mapped out an elaborate plot that covers level 1 all the way through level 30 and there are a number of surprises along the way. Those 'grand reveal' moments won’t be nearly as impactful if they’ve leaked out via plot summaries and/or an overview of where the Path is going. I can assure you that the current fears about the lack of a compelling archvillain, or a logically complete structure, or major NPCs, or a real hook are all misguided." This is nonsense of the highest order. A GM who wants to run the game sooner than later must simply have faith that the there will be compelling archvillian and that that archvillian will be a good match for his group. And the "grand reveal" moments are going to leak for the GMs who wisely choose to wait. Wizards has failed to help either group of GMs. (Of course this is further complicated by the fact that any player wanting access to Dragon magazine or the online tools is also paying for Dungeon as well. So the likelyhood of spoilers is much higher. This is yet another reason why bundling the digital D&D products is such a terrible idea.)