It seems you can find value on champions that others may not even try to read her skills and just follow what their favorite content creator recommends, I say you are playing this game right! 

I did recommend to fuse her into Rhazin in your last thread, so I feel I should take a closer look on Bloodfeather. So let's compare her to some other epic (or lower quality) singletarget hard hitters.

1. Hexia

Slightly higher attack than Bloodfeather (1564 vs. 1542). 

Hexia's best attack skills Soulreap and Spirit Harvest have damagemultipliers of 5.3 and 5.5 x ATK compared to Bloodfeather's 6.1 x ATK for Charged Shot. 

The bonusdamage for Hexia's Soulreap (self-debuff) is very situational, while Bloodfeather get's an extra 20% critchance and therefore could reach 100% much easier and probably while using crit-dam gloves.

Till now a clear 1 - 0 for Bloodfeather. On the other hand: Hexia get's an extraturn if she kills an enemy with Soulreap. 

2. Knight Errant

Only 1387 atk vs. 1542. But the damagemultiplier of 7 for Death Warrant A3 and damage-bonus of 75% (!) if at full hp result in a much higher damage than Bloodfeather can bring. I don't mention the weaken debuff, the enemy should be dead anyway.

The def of this Knight is absurd low, probably his armor has spikes on the inside and makes incoming hits even harder. But I don't think that's a big problem in arena. If used there at all, he is in a team that goes first and has to kill somebody, probably the debuffer or damagedealer of the opponent's team. Their speedbuffer is allowed to hit back, doesn't matter. I think I would prefer Knight Errant over Bloodfeather.

3. Ogryn Jailer

Only 1299 atk. Damagemultiplier for his Reprisal is 6.2 - but 20% damagebonus if the target has no active buffs, wich results in damage similar to Bloodfeather.

Multiplier for his Confiscate is 6 x atk - and one extrahit if a buff is stolen (Shield set or other buffs that work in the beginning of the fight come in mind). Chance for stealing (booked) 75%.

I think Bloodfeather is ok as singletarget damagedealer, but I'm not overwhelmed compared to the other options.

It's ok, man. It's not like I'm mad about it or something. I just found while playing the game on ways to use what I have. And I think using Affinities is also a thing whenever possible. I think Bloodfeather is, mainly, a Magic killer. But she won't survive long against Spirit champs. And as a non-S-Tier, any Endgame champ will swat her off the table. 

It's a matter of perspective and team building. And mine is that she can still be used when available. But if you have something better, go for it.