I'm starting a campaign with some friends soon, and have them here on D&DBeyond so I can track their character sheets and share content with them. As a DM I love that I can go into their full sheet and even edit things. But I'd love to see something in the DM section of a campaign that would compile basic information of all the characters at a glance. Things like their AC, HP, and Passive Perception scores. Maybe also things like saving throws, ability scores, and initiative.

Then I could just have that screen open on my notebook while we're playing for quick reference.

I believe this is something they are working on. The Encounter Builder tools will display some of this information as well.

I would further add the ability to add NOTES to the ADVENTURES, something like on a kindle where they are marked inline to the text.

This would be a great addon to campaigns. 

I'm personally using a printed sheet like that i found on Dungeon Masters Guild, having it build into dnd beyond would be splendid. It could even have place for small ability socres and skills.

P.S.: If you'd like to know what exactly I'm using PM me.