When starting a DU, OpenRoads creates a whole DU project inside the file and brings a lot of hidroly/hidraulic properties with it.

That's fine if the goal is to run an analysis.

But what if I just want to model a whole network and never run it? Didn't I just got a very heavy file with a lot of unwanted/unused data?

And that is my point. If we could have a model only workflow that would be great. The software doesn't need to know if a node is an inlet, manhole or an outlet or its headloss or manage various scenarios or prototypes.

Just model nodes and conections, elevations, descriptions and features. Kind of like modeling a MEP network. (heavy looking at OpenPlant or OpenBuildings MEP tools)