Hiya!
I'll make my list short'ish here.
I like a
general "Story Foundation" to the adventure to be explained in about half a page. If the whole adventure can be summed up in two or three sentences, that's perfect. (ex: read the 'blurb' on the cover of just about any 1e AD&D adventure module).
I like
simplified stat block, and, this is important,
a note of what book and page to find the creature! I'm almost equally happy with just a name followed by the book/page to find the creature on. If we are shooting for perfection...then how Kenzer & Co., did their Hackmaster 4th Ed modules. Here's a direct link to the "
Battle Sheet" for "Quest for the Unknown":
http://www.kenzerco.com/Orpg/hackmaster/downloads/product_pdfs/quest_battlesheets.pdf
IMNSHO, this is sort of how I wrote my own adventures and adventure 'notes' back in '83 or so...although mine had primarily just HP's and maybe a note about something unusual. But man! When I saw the Battle Sheets for "Little Keep on the Borderland" I was sold.

You can DL a PDF Battle Sheet of every HM4 module they produced. Free. They are also in the back of the actual module.
Ok. Other than a story foundation and a Battle Sheet, I also want an adventure to
mostly be written with virtually no acknowledgement that PC's will be involved to 'stop' the bad guys. Nothing annoys me more than seeing a page and a half of "tactics, motivations, and what-if's" for some NPC or monster! (sorry for those that love 'em!

). I don't need to know all that. I need "Grovhol is hoping to curry favour with his 'owner', Mistress Renna. Grovhol will risk his life to protect her secret". That's it. I don't need to know the particulars of why he wants to get on her good side, nor do I need to know what lengths he will go to in order to keep her secret safe. I'm the DM, I can role-play that on my own.
Maps that favour UTILITY and READABILITY over "Artistry". Give me an old blue-map of ye good ol' days! Easier on the eyes, easier to modify if needed, and easier to print out (ink-usage wise).
Random Encounter Charts? YES PLEASE! 
I just love 'em! They really make the game feel like it's a living, breathing, "setting". I'd say about a third of all my memorable play moments come from Random Encounter tables. They are 'unexpected' for both me and my players. They give us all a bit of that wonder and surprise that we all can just ad-lib and let the joint creative juices flow! Mmmmm.....
Lastly, I want it to
NOT be in "colourful book" format. I want it to be in the old detached cover and booklet format like the original Basic D&D and 1e AD&D modules (B2, B3, L2, S4, etc). Oh, and on
non-glossy pages! I absolutely *loathe* 'colour glossy pages' for anything that I'm expected to read and be staring at for 4 to 6 hours.
^_^
Paul L. Ming