I reached the same conclusion after comparing diagram-as-code tools — D2 feels cleaner and more expressive than Mermaid.

I’ve been working on an AI diagramming tool built around D2: https://aidiagrammaker.com/ You describe a system in plain English, and it generates architecture diagrams, flowcharts, and sequence diagrams in D2.

Edits can be made either directly in the D2 code or via a context-aware editor.