In addition, everything is getting a fully-fleshed out stat block, including ALL the dragons.
I want to expand on that a little bit.
We are definitely treating the PDF as a different product entirely from the printed book.
For the PDF, because "page count" is not an issue, every single monster will have its own page. One statblock per page. We'll put in extra pages with the monsters grouped and then hyperlinked in every useful way we can imagine-- alphabetically, by type, by CR, etc.
This is how I run my games, and it's very handy:
Game day, before the session, I print out the stat blocks I need. Goblin. Bugbear. Cockatrice. Medium Fire Elemental. Whatever.
Those pages end up behind my screen, with plenty of breathing room on each page and lots of white space to take notes during play. (Some might even call it wastefully extravagant to have so much white space to play with.)
Sometimes those pages roll over from session to session. Sometimes they get culled and tossed in the trash. Cockatrice only appears in that one room? I'll throw that page away at the end of the night. Or maybe just at the end of the "story arc."
Now, obviously, the book is another matter. It's simply not feasible to put each monster on its own page. For those, we'll have to fit more monsters per page. We'll do what we can to keep page breaks and column breaks as even as possible so that you'll never see two monsters on the same column. (Ick.)
This will end up being a lot more work, but the combination of PDF + Book will be a much stronger and useful product overall.