The Best Writeup I've Seen About Current DRK Status + Concerns - Check it out!

[Hundred]

The TP is so exaggerated.
Shield swipe is 210 potency, 40 TP.
You do 5.25 Potency per point of TP.
TP regen is 20 per second (updated every 3 seconds) Shield swipe is 16 TP per second at 2.5 GCD. 20-16 =4. Its an extra 4 TP based entirely on when you block.

Unmend is 150 potency, 0 TP. You do 150 potency, for no TP as its an MP skill.
TP regen is 20 per second(updated every 3 seconds) Unmend is 0 TP per second at 2.5s GCD. 20-0 = 20. You have full regen during it and as such 2.5 x 20 = 50. You regain 50 TP for every Unmend. (unless you have spell speed/Blood weapon active). Based on having sufficient MP to use it.

Let's take A4 for instance. The Manipulator hits you with magical damage you cannot block, if the fight actually lasted that long when a PLD ran out of TP given Shield swipe is entirely inapplicable they would have to wait. A drk would Unmend to keep up some damage, and then go back into attacking with TP skills.

The base TP expenditure for all tanks is 25.33 per second, this gets increased by skill speed.
Equilibrium heals 3.33 TP per second if used on cooldown while in Deliverance.
Blood weapon used on Cooldown puts Drk to 26.320346320346320346320346320346 a second.
Not attacking (Pacified) causes 100 TP to regen. GCD's that cost no TP recover 50 TP as well at base.
Thats why War's TP costs are greatly diminished at present.

PLD vs Drk TP is a joke. In a magical Fight PLD is intrinsically at a disadvantage as their options to replenish TP when @ while still "doing" something is well hit Flash lol. In a regular fight when they both run out, Drk will start spending mana for damage until they regain TP and PLD will simply wait. Given Drk already does more damage main tanking puh lease.

Drk's cross-classes are fine. Parry strength being consist 20% is fine and the consistency leaves it understandable for their general audience.