Dark knight while doing lower damage doesn't feel clunky, it's main issues outside of damage (which can easily be tuned) are more related to a couple of things:

1) Most of our mitigation comes from role skills, as we're literally just grabbing the ones removed from us. Outside of role skills, for mitigation we have TBN, Shadow Wall, and Dark Mind. If there's no real magic use in the fight then we have those two.

Paladins have Sentinel, Bulwark, Shelltron, Hallowed Ground (Can be used effectively as opposed to Living Dead which requires you to die for an effect), Clemency, and Passage of Arms. This is of course excluding the extra utility like Intervention or Cover. In addition they have their own stun so they get a free role skill that we normally would have to take. Throw in the shield mitigation while meeting or beating our dps and you see where some problems come in play. Warriors have good mitigation too but it's incredibly clunky to play and use right now.

TBN is not a free skill, you have to plan around boss' attacks as well as keeping mana reserved for it while also wanting your blood below 50 so it doesn't cap. It's a great addition to the kit and makes it fun to play, but it certainly doesn't ignore the mitigation issue.

2) We have some skills that just need hard tuning. TBN needs a couple seconds added to it because you generally have to early cast it or else the effect will come after the boss' attack. 5 seconds leaves very little room, especially if ping is involved. Dark Passenger was savagely nerfed, there's very, very, very few moments where it makes sense to use it as the mana cost is too high for the potency or the blind (which was also nerfed). Shadow wall is weaker by comparison to say Sentinel with nothing extra to make up for it. Quietus feels weak, it should be an oGCD or buffed. You literally should never dark arts Quietus as the mana should go toward Abyssal drains. Blood Price is not as good as Blood Weapon, and I don't mean for mana nerf on BP either, the 10% increase in speed is much more noticeable and fun to use. Delirium is okay but it's kind of just an extra button, there's no real skill involved with it. You pop it when it is up.

3) The job was redesigned around a lvl 68 and 70 ability. Why.