[shabble]

There's absolutely value in being able to partially generate (maybe just the nodes/edges, but without final layout), or possibly even just validate that a given diagram does actually match a given schema/definition, without necessarily solving the extremely hard problem of a good looking auto-layout.

I've dabbled in the past with trying to do auto-layout of new items while preserving explicit changes by hacking at some of the Cytoscape.js layout providers to heavily penalise moves to manually positioned nodes, but I've never managed to make anything close to what I'd call acceptable for general use.