My best guess is that Deflection is supposed to be looked at as a dodge type of effect i.e. a random chance to avoid incoming damage. The big thing that makes it different in this game is that because you will take a tiny bit damage from the attack, you'll still get all of the effects associated with that move. So, if it's…
Every class and mob stops to cast spells and attack. It's an overall design of the game and intentional. I think it will rarely be broken, and I seriously doubt it will ever be broken for any At-Will attacks.