Hi! I'm Dominic from the Mermaid product team. You raise some good points here. We released the whiteboard to help users get an exact layout they'd like, but it's in its early stages and is undergoing a lot of improvements.
I understand that automatic layout algos is one of the big draws of Mermaid since it creates a lot of speed, but our current layouts can get a little convoluted. I like your idea on creating a machine learning model, but I'm curious what your biggest pain points are or if you have any basic requirements for a readable and aesthetic diagram. Is it made with hard corners on edges? Rounded?
Would love to hear any thoughts you might have on this! You can email me at dominic@mermaidchart.com if you'd be willing to share. Thanks for your comment!