In a nutshell:
If possible, Evernote should try to implement a feature that allows u to hide and unhide sections by clicking on a headline.
I myself am a medical student, and when I write notes in Microbiology I typically make a notebook for that class, and notes on the bacterial genera (see screenshot). In these notes there are typically around 5 different bacteria with detailed descriptions about structure, clinical disease and so on. This arrangement works, but feels a bit overwhelming when I revisit my note. Too much information...
However, if I could hide and unhide the different bacteria (by clicking on the 'headlines') it would make it so mush easier to review my notes and find the things i'm looking for.
Hope it makes sense. If implemented correctly I'm sure this could be a GREAT HELP for many users.