The other night I was reading thru "Dwellers Of The Forbidden City" and I came upon an interesting enlightenment. A lot of the early adventures left room for DMs to make them their own. That's not to say that newer OSR releases don't do this as well. It did however remind of something. As a writer you cannot cover every possible outcome or idea that might crop up. In the back of "The Lost City", "Isle Of Dread" and "Dwellers" there are sections called "Further Adventures", these little paragraphs give you a few ideas on how to continue the campaign. I think there needs to be more of this in writing. Another thing I read just latetly was the idea of leaving out NPC names, and just having their standard title "baker", "blacksmith", "king" etc. The idea behind that is that it allows a DM to create their own names, to fit into their own campaign. An example is "Keep on the borderlands" which is open ended as far as NPC names are concerned. I'm also guessing that most of those early modules are at a very specific page count (I'd have to do some research, but my guess is 32). When you consider the amount of content in them, it's pretty startling how much there actually is. The caveat of course is that they couldn't cover everything.
Just something that was rolling around my head this morning.