From my experience, thats how a player based fear is designed to work. On my old Warrior there's a skill named "
Terror" It breaks Fear upon Damage. On Priest/Mage,
Freeze breaks upon being hit as well (not a fear but still a player based root). Im sure there's a couple more that do that as well beyond my knowlege. Its based on the toons kit, kit meaning it fits their role. If every root in the game were a mage's Lighting.. then Lightning wouldn't be very useful in that reality or rewarding for that class. If Lightning is Designed for a mage to root a target so that target doesn't move while the mage summons a 3 second cast (Flame), or if a Shadow Prison is designed for a rogue to easily get behind a target for blind stab, then
Saces's Scorn has a role for how its designed.
In my experience, in a PVP sw situation, i find it useful to cast it upon that Healer while the group you're with downs the dps first. Also very useful in escaping/tactical retreat. its just part of the locks nature as a "Support" as its classified to be by most.
But i do not believe Sace's Scorn is bugged