An aura is supposed to act like a force field. Mabey it shouldn't damage the player it touches, just nulls the effects of magic and blocks magic in the particular area. Thus of course, if this is to happen, Aura needs to be a tad bit smaller.
Oh yes, this would also prevent monsters from entering the aura, thus in turn if they do, they begin to die. So, all in all we are all happy. You guys get protection from players, and still get to kill monsters with the newbie spell.