We have requirements to allow for more customisation of the appearance of the flows and nodes. This isn't for individual users of Node-RED, but projects that want to adopt/re-use the editor, but have quite specific requirements on look/feel of the flow diagrams.
So at some point next year, all of the flow drawing code is going to be ripped apart and made pluggable. It's this work that might break the nodes that do extra-curricula drawing in the workspace.
But it's also that work that could allow for vanilla Node-RED nodes to do something 'extra'.
At this point, there is no design work on any of this. I say next year as I hope to be able to get to it at some point in that time frame. It all depends on what progress we are able to make on everything else.