I assigned Edit -> Deselect to a keypress whilst exploring that, and .. it wasn't pretty.
But I think I had thoroughly upset the apple cart during that session, as I was having all kinds of odd results. Things I need to run down again for duplication.
I really want to say though, that it sure seems like hitting ESC with the Selection Tool and other tools in when behaving similarly to the Select Tool, that ESC would deselect the item.
If for no other reason than that Edit -> Deselect right now, does not have a key assigned to it, and you can see where using some of the tools on successive objects does not really flow. As I show, so I've rotated that object, now I want to select another one. If Deselect is what is required, and as default has no assigned key, that makes things a bit more of a hassle.