The older adventure modules, even the ones with canned boxed text, assumed that the DM would be tinkering with and modifying the material prior to play. Descriptions of room contents were certainly provided but the presentation of said contents was up to the DM. Some things might be readily apparent and others might require closer investigation.
Short stat blocks certainly help the adventure from taking up too many pages.
My biggest problem with the format of adventures I have seen recently is the lack of maps. The last 4E module I picked up, Orcs of Stonefang Pass, had nothing but tactical combat maps of the individual encounter areas.
There was no map of the region, the village the adventure began in, or even a comprehensive map of the pass itself. Maps of varying scale help show how different areas are connected. Not every map needs to be presented at the 5' square scale to be used for combat. If the adventure begins in a village a simple map showing the relationship of the buildings in the village and a small area map showing the village and it's relative location to the adventure site might be helpful.
Without a greater framework, the encounter areas just feel like disconnected acts in a play. The environment doesn't feel complete and connected to a larger world. It is these kinds of details that help the adventure site feel like it belongs as part of the game world and feel less like a battle board.