I work with a utility company, and when they create new work in our ArcGIS Online web app, they are not able to merge/dissolve multiple line segments into a single feature (multi or single part).
As an example: they may be adding new conductor and there is a T-intersection. The current environment in AGOL does not allow that to be captured as a single line segment, yet they should all be considered part of the same line for purposes of attributes, including length calculations.
Ideally any solution would allow for the the edits to be made within the existing feature service rather than creating a new one.