If I was still playing with keyboard and mouse, I would probably not like to add another hotkey as a workaround for the point’n’click mechanic. If you play with a gamepad, you will not have this issue. But it has its own drawback: your auto-attack will not move-to-attack towards enemies in melee.
I admit this does not fully address your request. Maybe the next expansion and its new movement skills will mitigate the issue for you.
Can you tell us how often you need to retreat this way? Can you not fight through the surrounding mobs? And are you not enjoying the thrill of being threatened?