1. awesome ~ this seems to be in a sweet spot! (yes, mermaid is fine; but often looks bad - esp when visualizing large diagrams)
2. it would be great to have this as a layouting layer for C4
3. which brings me to a suggestion: i think it would make sense to allow for decoupling the topological parts of the language (arrows, groupings, etc) from the layouting concerns (left of, right of, etc)