Personally, beyond needed monsters and named NPC's (both great suggestions) here are a few other things I wish they did more consistently in adventures:
1. I miss having the old-school jackets with the maps printed on the inside or a book of maps that is separate from maps being printed on the inside of the module where you have to constantly flip back and forth (unless you print out the maps). I also realize this is kinda a trade-off to having hard-bound adventures also. Thankfully there third parties that are doing that for current 5E adventures.
2. I prefer to have shorter, more focused descriptions of a location that helps the theater of the mind type of play. Too often these current descriptions have too much dialogue and not enough focus on the environment. If the DM knows the motifs of the NPC's in a room, they should be able to fabricate the proper dialogue.
3. A format where each page is a single room with stat blocks better organized. For all of the faults of 4E I really liked some of the formatting they presented in their adventures. If you go back to some of the 1E modules, it is amazing how much stuff they cram on a single page.
4. I like having useful art in modules. A simple picture can go a long way in firing up the imagination of players and creating excitement at a table. Some of the older modules (like the old S-Series) included some great art that really enhanced play. The artwork found throughout the new 5E adventures is mostly top-knotch, but it is not as functional to use in-game.
5. More Module Support - I really like how these 5E adventures have included support (like 3rd party DM screens, props, miniatures...) but I wish there was even more. What if they had a downloadable PDF workbook that had a stat blocks with individual HP lines (similar to what Balfore was suggesting) that you could readily take notes and scribble in? Having these "battlesheets" if you will would make DMing much easier. Then you could concentrate in putting all kinds of other useful source book-like information and scenarios in the actual hardcover and not have to worry about space being taken up for stat blocks.
Anyway, just a couple of suggestions.