Use case or problem
The core aspect of Obsidian is that it is a note taking app, with notes that can be organized and linked in non-standardized fashion. The Obsidian app seems like it even encourages mind-map style notes, with the inclusion of the graph-view. However, a real graph view, would have customizable nodes shapes and arrow shapes. I believe this would open up a whole new world of possibilities in Obsidian. Customized arrows and nodes would allow you to create real world project diagrams solely in Obsidian (for example, UML diagrams). It would also allow an extra layer of organization and tagging for the note taker, that would visually be able to distinguish between nodes and the relations of these nodes. For example, an optional link, could be represented as a dotted arrow. You could even customize arrow tips and colours.
Proposed solution
Currently I don’t see any implementation that customizes the graph-view to the extent I wish for it to be customized.
Current workaround (optional)
There is a plug-in called Juggl, but it doesn’t do the basic in a way that modifies the graph-view itself.