Because of item 4 “Fully constrained sketches go crazy when inserting a single node” and to speed up quick designs we would need an Auto-Dimension / Auto-Constraints option just like in regular sketch. End routes if not connected and hanging up in the air they should be dimension to any visible planes (included geometry) but if at least one endpoint is connected then dimensions and constraints should be enough to create a fully constrained sketch.
@dan_szymanski