Well they aren't 'poor', per se. In fact, both of these skills are great if you're running something like Desperation, Vantage, Brazens, Sealed Falchion, Wrath, and more. Low HP skills are great for a skill like that.
No, they're poor. They do nothing if you haven't taken much damage yet, and even when you're on 1HP they're still not that good. There's nowhere near enough payoff to justify their inconsistency.
I am somewhat agree with this.
they might only work well with fury desperation.
but their inconsistency is what killing them vs their relative glimmer/moonbow family.
Wow vicious
I hadn't considered how good it can be with desperation
It can actually be more consistent than moonbow or glimmer, both of which are dependent on the opponent's def/res stat.
Have you considered wrath? I once saw a similar build on Karel, who's maybe approximately as good because he doesn't hit as hard naturally but his prf gives +10 on the reprisal. You also get it charged up for free on player phase this way.