Just something I came up because I'm really bored 5.3 - 5.4 does not look promising to me at all.
Dark Side
Acquire : Lv.30 [automatically received along with other skill when unlock DRK]
MP regeneration stops during battle.
Reduce GCD speed to 2.0s
Drains 500 MP for every gcd.
MP refreshing statuses have no effect. Effect ends upon reuse or when MP is 0.
Recast Time 30s.
Blood Price
Acquire Lv.30 DRK Job quest Ishgardain's Justice
Restores Your MP when You or Party Member within a radius of 15 yalms receive damage [1% of Max MP for every 1% of max HP loss while blood price is active. Calculate from damage received so damage to shield always included]
Effect Fade when 30% of max MP restored by Blood Price.
Duration: 30s
Recast Time 45s.
[Dark Art]
Acquire Lv 35 DRK Job quest "The Voice in the Abyss"
Enhance other Job Actions.
Can only be used while under effect of Darkside.
Cost : 2000 MP.
Duration 30s.
Effect fade after combo.
"Shadow Skin"
Acquire : Lv.28 [automatically received along with other skill when unlock DRK]
reduce damage receive by 15%. Upgraded to The Blackest Night after complete DRK JOB Quest LV 70 "Our Compromise"
Recast Time 60s
Duration 10s
Dark Art combo : Increase Duration to 20s.
Dark Missionary : Merge with Dark Mind.
Dark Mind
Acquired : LV.50 instead of LV.45
Reduces magic vulnerability by 20%.
Duration 10s
Recast Time : 60s
Dark Art combo : Grant Dark Missionary to all party members [except DRK who use it] within a radius of 15 yalms.
Dark Missionary : Reduces magic damage taken by 15%. [Convert magic damage mitigated by Dark Missionary on party member to mp and restore it on DRK. Maximum MP that can be restore = 2000 MP]
Duration 15s
New Living Dead
Living Dead Duration: 10
Grants the effect of Living Dead. While under the effect of Living Dead, most attacks will not lower your HP below 1. When HP is reduced to 1 while under the effect of Living Dead, instead of becoming KO'd, you will receive the debuff "Walking Dead
Walking Dead Duration: 10 [Increases HP recovery via healing actions on self by 50%]
If, before the debuff Walking Dead timer runs out, HP is 50% restored, the Walking Dead debuff will be removed. If 50% is not restored, you will be KO'd.
New "Sole Survivor"
Marks yourself with the status Survivor. When the effect expires , 30% of your maximum HP will be restored.
Acquired : LV.45
Duration: 10s
Recast Time : 120s
[by using Sole Survivor 1-2 secs before using the Living Dead it will ensure that we can remove Walking Dead before the timer run out because when Sole Survivor effect expired 1-2 secs before Walking Dead timer end we will restore 45% of our total hp [30% from Sole Survivor + 50% HP recovery boost = 45 %] now if we restore the rest of 5% earlier by using either Souleater/Abyssal Drain then our survival against Walking Dead debuff is pretty much guarantee. Healer probably don't have to waste much resource than it needed anymore should they need to heal DRK with Sole Survivor on cooldown since the required HP that needed to be heal is lowered to 50% and the Walking Dead also give HP recovery boost.]
[Ranged Pull]
Unmend
Acquire : Lv.15 [automatically received along with other skill when unlock DRK]
Deals unaspected damage with a potency of 150.
While under effect of Darkside using Unmend won't cost MP.
Additional Effect: Increased enmity
Dark Art combo : Radius increased to 5 yalms [became AOE]
[Gap Closer]
Plunge
Acquire Lv.54 DRK Job quest Kindred Spirit.
Delivers a jumping attack with a potency of 200.
Maximum Charges: 2 [after acquire lv78 Trait]
Cannot be executed while bound.
Recast Time : 30s
Dark Art combo : Maximum Range increased from 15 to 20 yalms, Potency increased to 400.
Low level Combo that replace slow slash&soul eater
Potency :
Spinning Slash = 200
Syphon Strike = 300
Delirium = 350
Blue Combo = Spinning Slash>Syphon Strike>Delirium [SS + Delirium = 3000mp]
*gif made from video about heavensward DRK recorded by Xanedia*
[While under effect of Darkside landing Delirium will change Spinning Slash,Syphon Strike and Delirium to Scourge,Carve and Split, and Power Slash]
Red Combo = Scourge>Carve and Split>Power Slash
Potency:
Scourge=350
Carve and Split=450
Power Slash=550

Scourge
Acquire : Lv 35
Can only be used while under effect of Darkside.
Carve and Split
Acquire by simply level up to Lv 56
Can only be used while under effect of Darkside.
POWER SLASH
Acquire by Complete Lv. 56 DRK Job quest Original Sin
Can only be used while under effect of Darkside.
Every time you landed any of these 3 skills you will get 1 stack of buff
3 stacks will turn Scourge,Cave and Split and Power Slash back to Spinning Slash,Syphon Strike and Delirium.
OGC ATTACK SKILL
Soul Eater
Acquire by Complete Lv. 60 DRK Job quest Absolution
Delivers an attack with a potency of 400.
Additional Effect : Restores own HP
Cure Potency: 300
Dark Art combo : Absorbs 100% of damage dealt as HP
Recast Time 60s.
Salted Earth = Merged with Abyssal Drain
Abyssal Drain
Acquire : Lv 52
Abyssal Drain won't instant heal with 200 cure potency x number of targets hit like in Shadowbringer
but it will make the target suffer dot for 15s
You fire the Abyssal Drain at the target and then the Salted Earth will be place where it hit and remain there for 15s
The Salted Earth aoe pool that spawn where Abyssal Drain hit will continue to heal you 100 Cure Potency x number targets inside the aoe pool for 15s [1 time every 3 secs] [It work like how SCH's faerie heal drk over time just different in visual which in this case the Salted Earth aoe pool is the Faerie and there's no green tether tied you to it but if a target leave the pool you will stop get a heal over time]
In the boss fight or a single target, it might help a little bit to lessen the hp lose against the auto attack but it won't be able to heal much like in large pull.
You also don't lose much if boss move away from the aoe pool since there're usually 2 situations that this happen
1 boss move away for mechanic and start casting something and stop auto attack you
2 when you have to pull boss away to avoid aoe/ heavy attack.
And here come another attack OGC [single target]
Something that using the Stormblood's Reprisal attack animation!

Of all the changes I want this the most
"Nameless Skill"
Acquired : Lv 54
Max potency = 400-500-600-700
Recast Time 60s.
This ocg will deal moderate or big damage according to how long the target suffered from dot from Abyssal Drain. At 1-3s left it will deal the most damage it could and ensure Critical Direct Hit.
but I'm not sure how server will handle it. At any rate it have the potential to yield high reward but require precise timing and management to earn it.
AOE GCD
Stalwart Soul replace Unleash
[reason is because when moving while using unleash you character move but there's no leg movement. It look toooo obvious that you just floating and sliding on the ground like T-posing] "Skating during Unleash looks horrid and is overtly apparent - largely because you almost always use the skill while moving. Painfully reminiscent of Quake 2 multiplayer."
Potency : 150
Reduce Blood Price recast time by 5s.
Reduce Blood Weapon recast time by 1s.
Effect does not stack when hitting multiple targets with a single attack
Quietus
Acquire : Lv 40
Will be the second aoe and gain combo bonus from Stalwart Soul.
[swap place with the original Stalwart Soul and acquire at lv 40 instead.]
Potency : 200
Combo bonus : Restore 800 MP
Reduce Blood Price recast time by 5s.
Reduce Blood Weapon recast time by 1s.
Effect does not stack when hitting multiple targets with a single attack
Mitigation
The Blackest Night
Acquire : Lv70 DRK JOB Quest LV 70 "Our Compromise"
[2000 mp] shield will be nerfed to 20% of max hp and give mp back when it break.
Recast Time : 15s.
Skill Acquire at high level [Shadowbringers]
Blood Weapon
Acquire : Lv 72.
Grant 5 stack of Blood Weapon, each stack allowing you to increases Blood Gauge by 20 and restores MP by 200 upon upon landing weaponskills.
Effect does not stack when hitting multiple targets with a single attack.
Duration increase to 30s.
Recast Time 90s.
Bloodspiller
Animation shortened. First Part Cut out


Acquire : Lv.72
Blood Gauge Cost: 50
Potency : 500
Dark Art Combo : It will have a more bigger explosion [Dragon Fire Drive's explosion but it's dark/purple flame] Potency 800.
Dark Passenger
Acquire : lv 74.
Blood Gauge Cost: 50
Potency : 400
Dark Art Combo : It will have a big wave of dark blade[Big Dark Hissatsu: Guren effect] Potency 700.
Flood/Edge =Remove.