I agree, I've posted this before as a suggested change that would actually make Darkights engaging again imo.
Dark Knight Changes:
Remove the auto darkside and turn it into an OGCD toggle
When not in darkside all moves give mana back
When in darkside mana is constantly drained, the final move in the weaponskill combo and all OGCD all cost mana but all heal the Dark Knight.
Obviously numbers for this need balancing to not make it OP but ideally keep the cost of the abilities low but keep the constant mana drain moderate, the aim would be to balance the mana gain outside of darkside with mana cost of being in darkside, similar to the original design.
Take quietus and bloodspiller off the blood meter
Unlink C&S and Abysall drain
Remove the current delirium and bring back the old weaponskill
New move Overwhelming Darkness to replace living dead. Fills all darknight resources mana/blood/darkside meter, resources and health regen increased massively overtime for 15 seconds after 15seconds all meters are zero'd regardless of state when the ability ends and all gain for these meters are blocked for 5seconds.
Moveset Change:
Weaponskills to reflect what stance you're in. None darkside you're effectively just using a greatsword, in darkside you start using some of the more darkness themed moves.
None Darkside weaponskill combo
1 Hard slash
2 Syphon strike
3 Delirum
In Darkside weaponskill combo
1 Souleater
2 Powerslash (our old combo finisher where we shot the blast from the hand)
3 Bloodspiller
OGCD non darkside
1. Unmend is now a OGCD
2. Scourge (bring it back)
3. Spinning slash (now aoe and a OCGD)
4: Carve and slice reduce cooldown to 18 seconds reduce damage
5: Plunge no change
OGCD darkside
1. Unmend becomes Abyssal drain
2. Scouge becomes Quietus
3. Spinning slash becomes Flood of Shadow
4. Carve and slice becomes Edge of Shadow
5. Plunge no change
6. Shadow bringer unchanged
UI Class bar changes
The counter for darkside is now the darkest night counter, instead of counting down it counts up while you're in darkside for however long you were in darkside. This is the resource pool for TBN and living shadow, at 50 is used to cast TBN, living shadow can be triggered any point over 50 but last longer the more you use. Add in a second press to living shadow allowing the DRK to destroy the shadow early to return a portion of the cost to the counter.
Keep the blood gauge but give us a move that lets you absorb a portion of the blood gauge to either give a chunk of mana or heal depending on whether you're in darkside or not you could use the old dark arts animation for it.
(In a later change I would like to see this as a modifier like dark arts was adding de buffs but would require lots of work.)