We would work on a range of visualisations of the nodes as appropriate and of the constraints (arcs) as appropriate. Some of which would be far from an actual boxes and lines drawing.
We would like to have autolayout of some of the visualisations, with the ability for a user to modify the automated suggestions to improve the look.
If we add an Issue visualiser to the nodes and constraints (arcs) level, then we will have a basic interface that we can perhaps carry though a lot of our work.
This layer could then sit as a tool building component under the actual process editor , process panel and other applications.