In anycase, we'll definitely need a key to exit that mode, because I doubt we will have enough keys on our keyboard to assign hotkeys to every little thing in the menu, much less be able to remember all of them without checking the options menu.
But yea there are times where that would be great, and yes, if ranged weapons are implemented anytime soon, it'll be very useful. Personally though, I don't like ranged weapons. They're usually too weak, require aim, and they're useless at close range. Besides, what else is magic for?