I think it's fair. I use FreeCAD a lot, and the word I would use last to describe the UI is "discoverable". Ignoring whether a workflow is possible - whether the functionality exists at all - there's a whole lot of it that you have to Just Know, or equally as often Just Know That It's Not Actually Broken. The very fact that you started your comment with "If you <do X thing that you have to be told to do>" is precisely part of that.