Nerfing Blood Weapon, Dark Passenger, and not understanding that Dark Knight needs buffs to Dark Dance in a different manner just proves how little you know about the Job. Clemency restoring TP is completely unneeded unless they throw another juggernaut boss like the Manipulator at us, and the Divine Veil buff is unneeded, the range increase might be nice though.
Edit: If you want Dark Knight to function better as an off-tank, all they need is one ability added: Shadow Spikes.
Code:
Shadow Spikes
Cast: 3s
Recast: 2.5s
MP Cost: 884
Coats target party member or self in a layer of vicious spikes.
These spikes deliver an attack with a potency of 10 every time physical damage is suffered for 30 minutes.
If cast on a party member, potency is halved, however any parries or blocks performed by the party member will act as if the Dark Knight had parried the attack.
Can only be active on one target at a time.
If you wanted to go one step further, just remove the PvP requirement to Sole Survivor's secondary effect.