===Edit:===
A thought occurred to me on how much impact Delirium and Bloodspiller has in our damage output in contrast to Edge of Shadows
Source taken from a 99 percentile log on Idol of Darkness savage.
Total Bloodspillers 600
Casts 63
Potency 37,800
Delirious Bloodspillers 600
Delirium 7
Casts 35
Potency 21,000
Natural Bloodspillers 600
Casts 28
Potency 16,800
Edge of Shadows 500
Casts 42
Potency 21,000
TLDR Delirium is making Bloodspiller overused and usurping Edge of Shadows(otherwise known as new Dark Arts) as DRK's iconic skill. The devs seem to also support the notion of intending Edge of Shadow to be DRKs power attack with the tankbuster from the DRK add in SoSex being Edge of Darkness instead of Bloodspiller.
Link to my own wishlist for DRK in another thread: https://forum.square-enix.com/ffxiv/...=1#post5501449
===Editv2===
In hindsight, Bloodspiller and Delirium Bloodspillers have less impact on DRK rotational impact due to them being a GCD(having to pay a cost in the GCDs they replace). Effectively a 300 Pot button over generic Souleater combo potency average.
Total Bloodspillers 300
Casts 63
Potency 18,900
Delirious Bloodspillers 300
Delirium 7
Casts 35
Potency 10,500
Natural Bloodspillers 300
Casts 28
Potency 8400
Edge of Shadows 500
Casts 42
Potency 21,000
It should be noted that the value of Bloodspillers compared to the Souleater is arguably less than 300 due to Delirium Bloodspillers not generating any Blood and Natural Bloodspillers not generating any MP and Blood.
===Editv3===
because I couldn't leave it alone
Value of MP and Blood
Soul Eater combo generates 600mp. 600mp is 1/5th of Edge of Shadow making it effectively 100 Potency. (500/5)
Soul Eater being a 3 step combo, 200mp per GCD, 33.33 potency. (100/3)
Therefore the average potency value of a DRK gcd/Soul Eater combo GCD is 333.33. Making Natural Blood Spillers worth 267.77 over Soul Eater.
The Soul Eater combo generates 20 Blood gauge. 20 Blood is 2/5th of a Bloodspiller(Valued at 267.77), making 20 Blood worth 107.108. (267.77*0.4)
Soul Eater combo being 3 step, the value is further divided up into 35.7026 per GCD. (107.108/3)
True value of Bloodspiller is 232.0674 compared to the average potency of Souleater GCD that it replaces.
Delirious Bloodspillers 265.3974
Delirium 7
Casts 35
Potency 9,288.909
Natural Bloodspillers 232.0674
Casts 28
Potency 6497.8872
Total Bloodspillers
Casts 63
Potency 15786.7962
Edge of Shadows 500
Casts 42
Potency 21,000
I feel less dissatisfied about Bloodspiller and Delirium, but still demand Delirium be reworked to something that empowers our main resource/spender.