Annotate Your Own Notes
I'm a University student, and I would really like the ability to annotate -or add side-notes- to my notes, in a more orderly fashion than the current ability to create floating textboxes on the side.
Have you ever used the Kami PDF software? You know how it allows you to highlight / comment on a section of text, and the comment appears perfectly aligned with the highlighted text? Something like that would be perfect.
Take it one step further, and allow people you share the notebook with to have 'review access', allowing them to annotate your notes and have their comments properly signed with their Microsoft account name.
Alternatively, just get Kami working on an Add-In for OneNote to enable all of this stuff.