The Scene Graph is awesome!
I'm using it with my students (both in high school and academy) and it's really straightforward for them to realise how to use hierarchies with triggers and the like, or as a way to connect an avatar with its Platform-powered collision box in a platformer. It's much easier to explain game design with those nice green arrows than using containers.
Still, they always struggle with remembering how to create a hierarchic relationship within the editor. Hold Shift + select both + right-click on the parent + pick Hierarchy > Add selection to this instance = huge complication.
The way they (and I) think is: we want to draw the green arrow from the parent to the child. Therefore my suggestion is: Please add a feature where you can just right-click on the parent and select Hierarchy > Add child: a green arrow would appear that can be connected to the child object.
Please tell me your opinion.