This melee should be a one shot kill. The reason why is that it requires out of the ordinary actions of the player to proc. They have to run, slide, aim their slide, melee, and hope it hits the intended target in the first place. It's very skill based. It doesn't have to kill multiple Guardians (though that wouldn't be bad either, but we would be approaching very powerful/OP territory, but I think Titans have an AOE one shot melee too, I could be wrong) if it doesn't at least Hit multiple Guardians, it should do that too. But make the first full health Guardian it hits die on impact. I main Way of the Wraith Nightstalker. I don't even have this subclass unlocked I see no one or very few people using this class outside of the super. The melee is basically wasted. Reward the player for using it.