This suggestion needs to stop being brought up be everyone and their uncle. Anyone who makes it clearly fails to understand that dropping 4,800 MP on a party wide TBN would be a DPS loss regardless of how you use it. It's a bad idea, one of the worst ideas that keeps getting thrown around constantly, when Dark Knight doesn't necessarily need party utility, it just needs to have an identity.
In PvP I believe Sole Survivor just does this by default, and during the Media Tour Sole Survivor did so in PvE as well. That is the kind of party utility I could agree with, but adding Dark Arts to TBN is just... no.Dark arts + sole survivor= dmg up on target debuff.
Dark Knight needs help with mitigation, self sustain in single target encounters and MP costs, those are our biggest problems outside of raw numbers.
Dark Passenger is useless, people say two or more enemies is a gain, but frankly in an AoE situation I'm using DA Quietus because the blood is nigh endless and MP is going to be trivial. DP could have a nice niche if its cost were lowered or it simply didn't cost anything.
They could make the MP restore from Syphon Strike the same in and out of Grit and tie the HP restore from Soul Eater to Dark Arts—like it should be.
Change Sole Survivor to grant a 5% Vuln up on a target, while restoring partial HP and MP to the Dark Knight comparative to the damage sustained by the target during its duration, making it party utility, but also self sustain.
Then the final change I feel they need to make is with Shadow Wall, either the effect needs to be increased, or the recast time needs to be made the same as Sentinel.
That said, I don't expect any of that or anything similar, because they've proven time and time and time and again that they have no idea what to do with Dark Knight. It's almost like they got it right when it was introduced? A novel concept, one they clearly fail to understand. In all honestly, with the sweeping changes they did to WAR in this and every-single-patch, 4.25 or 4.3 better be DRK's time for an overhaul because this is just getting stupid.