It's very common that as a UXDesigner you have objects on top of another object, but you need to change or add an objekt under.
This becomes very tedious today as there is no quick way to select an object that is below.
A shortcut such as Alt+leftmouse to cycle through would solve this.
It is also tedious that you always send something to the end of the back when you send something back in the layer order.
A send back one step instead of all steps.
I understand this might be difficult as the order of objects might not be local, this makes it even more important to be able to cycle through objects when you click.