The reason this one feels distracting to me is the animation, and the use of force-directed graph layout. Graph layout is hard but I hope they can implement Sugiyama or something instead.
Instead of animation, they could do something like showing deleted nodes in red and new nodes in green, a bit like online chess.
Maybe I'll send a PR their way..
Implementing custom visualizations is super easy! See [3] for a very simple example. If you implement a visualization there, it will be available for all people that use the visualization framework (e.g. extensions for other IDEs), not only this extension.
[1] https://hediet.github.io/visualization/?darkTheme=1&state=XQ...
[2] https://hediet.github.io/visualization/?darkTheme=1&state=XQ...
[3] https://github.com/hediet/visualization/blob/33de54d69624e1d...
Using it feels very different from a traditional debugger where you need to control every step: it's often sufficient to just observe passively and note when incorrect patterns surface.
As an example, http://db48x.net/reposurgeon/pathmap-diagrams/generated-path... is one of the graphs I generated.
Have you published the server and the protocol anywhere? I'd use it even though I would have to write the client side myself. For my project it would even be desirable to write the client side twice; I'm porting a program from one language to another, and it would be amazing to be able to compare the implementations visually.
If you're fast stepping through code trying to confirm it working or finding a bug, you're going to be annoyed by the time it takes the visualization to finish on each step.