What functionality is missing? What is unsatisfying with the current situation?

  Currently there are no check for large changes in whiteboards, even changes to style and complete content deletion of a whiteboard simultaneously.   This can lead to, for example, the hypothetical event where you accidentally hit a random link in world anvil, then, because that was an accident, you were to click back, and it deletes everything you did. All of it. An hour or two of work, gone in instant. With both the style and content removed.   I am of the belief that you could add in a simple check here, either checking if large amounts of data will be deleted when you load or checking that combined with style edits or other combinations that would not naturally occur through the GUI.   Hopefully, it is possible to do it in an efficient manner, I don't know their database structure, but even if not, it would be great if World Anvil stopped deleting the contents of my whiteboards.,checks  

How does this feature request address the current situation?

By adding a confirmation popup in this event, you would stop the issue entierly, especially if the fdefault action was to not save it until you have spesifically told it that it was on purpose.  

What are other uses for this feature request?

It would also potentially stop other instances of accidental deletion in whiteboards, such as if you were to close down your computer, and forgot to close an open tab with a whiteboard in it.