Just downed Paragon of Klaxxi last night and was surprised that the "Aim" mechanic could not be deterenced by hunters in order to solo soak it. Not sure if its a bug or intended but our mages were able to Iceblock it AND use greater invis to totally counteract it, in addition our SPs were able to use Dispersion. Deterence makes no sense sometimes to me.
Deterrence is one of those spells blizzard decides when we can use. There's very little consistency.