One of the big negatives with the 256-page tome style of book is that the monsters are always conveniently located in the back of the book. So when you run a combat, you often have to save your previous spot and turn to the back of the hardcover, use the monster, and then flip back to your original spot. Literally the only space-saving thing they do (aside from, in the case of OOtA, repeatedly referring the reader to the DMG rules for poison) is to not have any stat blocks in the middle of the text. It's really a shame that 5e's monster format doesn't allow for a "quick view" so that we could have nice, compact monster listings along with the running text.
At the prices we're paying, if boxed sets could be done for $10 or even $20 more, I'd gladly pay it. For instance, with OOtA, I'd picture four booklets. You have one called "Into Darkness" covering chapters 1-7, and one called "Against the Demon Lords" covering chapters 8-17. Both could be sturdy perfect-bound softcovers. Then you'd have a big poster map of the Underdark hex map on page 19, and a separate booklet with all the other maps in the adventure. Then, one more booklet, this one saddle-stitched, with all of the appendices. You could even have cardstock sheets with all of the NPC stat blocks that get distributed to the players in chapter 8. WotC seemed willing to play with boxed sets in the 4e era, but has since retreated, which is a shame. An adventure this big deserves one.