Just for some players here in this topic:
Definiton of stun:
Stun is a status effect that prevents active actions like moving, turning, using spells, items, but does not prevent passive abilities, such as evasion, damage block. Stuns also interrupt any casting or channeling spells and attacks.
To get back to the topic:
Ferocity improves the variety in pvp, I think it is very nice for low/mid amp players, but it gives too much advantages for high amp players. I think a "turned progression" (more bonus for lower dmg and less bonus for higher dmg) would be a solution.
At the moment ferocity is totally useless for all healing classes, so I suggest that it also enhances your heal.