Currently the data canvas shows any transformations, row/column additions, and data functions applied to a single, foundation, table. For complicated dashboards that require data flow over multiple tables (and between IronPython and TERR scripts) we sometimes have to build out Visio diagrams to keep track of how they work, and to document them for future development/maintenance.
My idea would be for Spotfire to visualise all of the interactions that are currently accessible in the data canvas, but to do so over multiple tables.