[graphviz]

It would be great to see new practical software for declarative specification of general 2D diagrams. With increasing emphasis recently on language-based tools, this is an excellent opportunity.

It would be good to find ways to make the internal algorithms and their parameters more "open" or more easily parameterized and recombined in novel ways. It would be good to find ways to rely on more generic optimization methods, though software like this is probably skating on the edge of computational intractability (not to mention usability or interpretability issues) so it's a very challenging problem.

Kudos.