OK, I've revised my original post with an update of the various conversations we had over the past months. Here are what folks on ENWorld want in a published adventure...
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OVERLAP
Boxed text, direction-neutral & concise – (8) Lanefan, transtemporal, LordEntrails, Charles Rampant, Schmoe, happy hermit, ArwensDaughter, ad_hoc
Good useful comprehensive maps (before area descriptions) – (6) LordEntrails, ExploderWizard, vincegetorix, Eltab, Jester David, Charles Rampant
What ifs (player actions) & Monster plans/reactions – (6) Lanefan, transtemporal, ExploderWizard, Ibranteloth, ArwensDaughter, Li Shenron
Monsters/NPCs with motivations…and relationships! – (6) robus, ExploderWizard, hastur_nz, Charles Rampant, Ibranteloth, ArwensDaughter
3.5e/4e style full page encounters (segragated monsters, treasure, traps, etc) – (5) shoak1, aco175, Ibranteloth, LordEntrails, ArwensDaughter
Layout that's clear, useful at table, and condenses info while keeping it readable (e.g. 9 pt font, leading 11 pts, diminishing horizontal scale) – (4) Lanefan, steeldragons, hawkeyefan, ratskinner
Clearly connected encounters/plot progression for groups preferring linear narrative – (4) shoak1, LordEntrails, Eltab, LostSoul
1e style abbreviated monster stats in room descriptions – (5) Lanefan, steeldragons, Schmoe, JohnnyP71, LordEntrails
Monster stat appendix in the back (4) – Eltab, Schmoe, happyhermit, LordEntrails
Something different/new (magic item, monster, NPC, trap, spell, etc) (3) – Lanefan, Schmoe, Charles Rampant
Limited Backstory, relevant to players/they can find out – (3) Lanefan, shoak1, Yavathol
Modular bits – (3) Eltab, Jester David, happy hermit
Compiled index of all monsters used in the adventure for DM token/minis prep – (3) css, JohnnyP71, happy hermit
Limited scope, self-contained (3) – LordEntrails, css, Lanefan
Maps (separate/pull-out for DMs & players) – (3) robus, JohnnyP71, Lanefan
Subsystems or rules variants appropriate to adventure – (3) Charles Rampant, Tony Vargas, Lanefan
Event/story development track or flowchart, dynamic story, “if the players do nothing…” – (3) Lanefan, hastur_nz, Tobold
Inventive design & good/imaginative ideas – (2) hastur_nz, Jester David
Ways to limit rests – (2) shoak1, JohnnyP71
Index if needed – (2) LordEntrails, happy hermit
Fun-to-read, flowing writing, non-formulaic – (2) happy hermit, Charles Rampant
Chapters/section playable on their own – (2) Carmen Sbordone, Ibranteloth
Run with no prep – (2) Libramarian, Li Shenron
Printer-friendly / detachable map – (2) ArwensDaughter, Li Shenron
*Readable* in-line monster stats – (2) pogre, LordEntrails
OTHER COMMENTS
Dungeon with multiple ingress/egress points, loops, multiple methods between levels (some which skip levels), secret areas, intentional “holes”, length of stairs noted – Lanefan
No boxed text (esp. not wordy) – robus
Sensible wandering monsters or none – Lanefan
No random monsters – robus
Innovative use of environment – Ath-kethin
Include stuff that breaks rules without explanation, i.e. “the Weird Stuff” – Ath-kethin
Chapter synopses & conclusions – transtemporal
Natural, organic language/description – Luz
Level appropriate encounters & treasure – shoak1
Relationship maps if needed – LordEntrails
“Dungeon dressing” – ExploderWizard
More complex “skill challenges” like UA traps – vincegetorix
PDF reference sheet of rooms – fjw70
Catchy title – ccs
Evocative cover art – css
Use rarely used monsters – css
Printable PDF of maps 1 sq = 1 in – css
Real danger – css
Well-organized room descriptions – Schmoe
Multiple adventure threads, esp. in “setting”-type adventures – Schmoe
Hyperlinking (for PDF/digital adventures) – hawkeyefan
Teach new DMs how to run/design advanced games – Jester David
Introduction providing breakdown of story beats & where to find stuff – Jester David
Town/region for the DM’s further use (e.g. Hommlet or Phandalin) – Charles Rampant
Using PC Backgrounds as hooks – Yavathol
Sandbox with an overarching plot – Inchoroi
Level/level range on cover – Ath-kethin
Plot twists – Yatzromo
Chance of failure, PCs have to earn success – Yatzromo
Intelligent monster strategies – Ibranteloth
Bonus materials online (e.g. printable maps, design/playtest notes) – Ibranteloth
3D dungeons, ideally isometric maps – Ibranteloth
Strong hook, get me interested in first page or two – Zardnaar
Monster/NPC cards – ArwensDaughter
Tips on adjusting adventure for party size/level – ArwensDaughter
No “fill this room with something” blanks – Li Shenron
No new monsters – Li Shenron
“Good” random encounters – ad_hoc
*Compressed* in-line monster stats – Lanefan