I know high quality splines are a long way off, but including POLYLINES in Revit's toolset would be a big improvement to core functionality. In Dynamo one frequently desires to reference a compound path. If Revit supported polylines, the user wouldn't have to draw multiple line segments, make a model group, then reference the group into dynamo and get group elements, then join the segments to form a polyline to work from. A combination of adaptive point type behavior would be of great benefit (3d snapping). Line endpoints could exist in the model independent of a workplane or with a much more liberal relationship to a WP. Allowing CLOSED polylines would be even better.