Mind mapping tools
Mind maps/concept maps are used widely in education. Whiteboard should add mind-mapping tools including arrows that can snap to notes/pictures/objects. This functionality exists in PowerPoint but on PowerPoint the canvas is often too small for collaborative mind mapping.
Johan Bouvin commented
Using "Ink to Shape" in Powerpoint (Draw tab) is brilliant! I had never noticed that it exists until I looked for a mind map suggestion for whiteboard to vote on and found this. Thanks Dave! Great if the feature could be made more prominent and easily discoverable in Whiteboard.
Also, chosing the type of arrow heads on the connectors would be good.