I’m not sure what you mean by kinks. The input is a control polygon, so it’s all degree 1. The input sorting is literally the exact same as with _Join. If G0 then join, else don’t. The only thing needed for this feature request is to use the existing _Join command to prefilter the input when the option is selected.
I’m not sure if this make history replays more complicated, but you would again send the input through the _Join prefilter and run _CurveThroughPolyline as it already exists.