I would like to have a button that would hide/show dock, remembering left position.
What about View > Now playing or CTRL+F12 (or which key you prefer to bind the action to?)
Shortcuts are great, but a visible button would be more user friendly, specially for ocasional users.
At the moment we cannot find a logical place to put this control in the UI so we will not implement it for now. Since the function can be accessed via menu/shortcut we rate it as a minor thing.
Possibly to implemented later.