Okay, back to the subject.

The 4E DMG is replete with advice about needing to know the outline of your adventures and campaigns and how to help get and keep your players on track (chapters 6
Adventures and 8
Campaigns specifically). The biggest peice of advice, provided multiple times, is sketch an outline or overview, albeit a loose one, so you know where you are heading.
quote DMG pg. 141: "
Once you have some idea of how your campaign theme will shape the story and have developed a historical backdrop, you can sketch out its major events".
. . .
"If nothing else, though, you'll at least have an idea of the campaign's climax and how the characters can get there. When they stray from your outline - and they will - you'll have some sense of what. . . (to do). . . to get them back on course".
Without an overview, this is almost impossible for the DM. Without an overview of the AP, DM's are going to end up retconning events, and resorting to a certain amount of railroading in order to keep on track with the adventures as written. Now of course, DM's can deviate from an AP at will, and can adapt what they want or don't want. But, this nullifies the major advantage of an Adventure Path - convenience of pre-preperation. With an AP the DM doesn't have to come up with all of the things the DMG talks about concerning making adventures and campaigns. However,
without an overview for the DM, it's just another collection of random adventures, no different than any other adventure in Dungeon.
So, in short WoTC, without an overview for the DM you have eliminated the APs' strongest selling point. Doesn't seem like the best way to do business. Personally, I will not pay for an incomplete product.