I find it really useful to be able to angle objects to maximize build plate. I can make my changes within my CAD program, but I would hope to see something a little more comparable to Cura's object manipulation. I know about the ctr-left click to move the object, only helps slightly.
It already has object rotation. You can use alt-click with the mouse to do this in real-time or double-click on the part if you want to enter a specific angle.
You might want to read the quick start guide if you haven't already. It explains all of these mouse and keyboard shortcuts