You forgot that you cannot have foreshadowing in play if you do not know what to foreshadow, and what can be cut for better playability or taste of the group.
This is untrue. There is foreshadowing in the first SoW module.[the note, the portal, the information on the Rivenroars]
A player wouldn't get the spoilers unless he wanted it.
This is a terribly naive view of the situation. I have neither played nor read Keep on the Shadowfell, but i know enough about the module just from off hand comments from people who have to get a good enough idea of what I can expect
Have you ever DMed? Your arguments sound as if you have no experience with DMing, at least not with DMing a campaign that's not just verbatim reading of a bought adventure. You really sound like you think all a DM has to (and can) do is read the adventure text.
I am DMing RoR quite successfully right now. Before that i DM'd a 4e adventure of my own making. Before that multiple 3e adventures of my own design. I've both directed and acted in amature productions.
Now that we have corrected the ad hominem there are a number of ways that things can be DM'd. Just as there are a number of ways that things can be directed. You can indeed direct while only knowing what has happened and not what will happen. Its actually easier to DM not knowing where things are going than it is to direct. Since a director needs to know the motivations
for his actors and a DM needs to know the motivations
of his actors. But both of these things are still rooted in the past and not the future. But a director needs to know what the actors characters want to do, and a DM doesn't. Or he can just ask.
What is happening here is a desire from many DMs to be both the director and the writer. And well, if you're using the plot of pre-made adventures then that boat has sailed, you've defeated the point already.
Are you telling me Star Wars would have been better if the director had NO idea what was going on in the movie?
When the audience
is the actors it can actually have a huge effect. Especially if your actors accidentally get your hands on parts of the script they should not. As someone who has DM'd, directed, and acted you certainly can direct and act without knowing where the action is going just as you can act without knowing where the action is going.
I can absolutely tell you that episodes 1-3 would have been better if no one had seen Episodes 4-6 before. Skywalker would have been a much more compelling figure if "you're going to become Darth Vader" was not hanging over the directors and actors head. The fall might have been striking and poignant instead a "Frodo, get on the boat already" moment prolonged for 3 movies.
Whats to stop a player from walking into any FLGS, picking up the adventure they are currently running, and flipping through it?
This complaint has been answered at least twice in the last page, stop bringing it up like its some revelation. It was even mentioned directly above the section you quoted in your discussion!
There is NO difference between spoiling the current adventure, and spoiling the entire one, so saying that argument is not valid is perposterous
Yes there is. Spoiling the entire part reveals more information than would be revealed by spoiling each and every adventure before it was played but after the previous one was. This is because the following adventures reveal information about previous adventures which would not be revealed otherwise.
edit: Note, if there was no difference between spoiling the current and entire set then there would be no reason to want the information. Since there is, as you said, no difference between knowing and not knowing.