Homages to previous games
It's worth noting that FFXIV sometimes incorporates several intersecting job concepts with a similar theme. As an example, it would be difficult to implement a unique Thief job which didn't also play similarly to Ninja. As a result, FFXIV's NIN incorporates flavour from both (such as the Mug ability).

Likewise, DRK lies at the intersection of several Final Fantasy archetypes. Dark Knights, Rune Knights, and Magic Knights are all variants on a theme. While they all have their nuances, it's difficult to incorporate all of these into the same game without running the risk of making them appear very similar. You can't really have a separate SOLDIER job wielding a Buster Sword when 2-handed swords are DRK weapons.

The solution is to pay homage to these reference jobs in the skillset, so that they are adequately represented. FFXI is a good starting reference for new actions, but there are plenty of iconic abilities that are yet to be represented in game outside of that.

Take Runic, for example. In FFVI, Celes uses this iconic ability to absorb spells and regain MP from them. It feels like a bit of a missed opportunity that TBN wasn't named after it. Even the animations are similar.

We've talked about DRK's relative lack of burst options. Consider the following: your Delirium buff keeps a running tally of your DA usages while it is active. At the end, you launch into a high-speed set of sword slashes based on the cumulative total, in the same vein as Omnislash.

What if PLD had Leo/Beatrix's Shock as a magical AoE? What if WHM used float to move without interrupting their spell casts? What if MCH had access to Edgar's Chainsaw or Bio Blaster? The series has a vast library of untapped abilities outside of what was presented in FFXI. I want to see more new abilities that pay homage to the series as a whole, instead of falling back on the usual upgrades to Stone 12 and Malefic 17 each expansion.

DRK in FFXIV
"Sacrifice is to renounce that which binds you. To recognise that which matters─and forsake all that does not."

FFXIV's Dark Knight, from a lore perspective, has some very important differences from other games in the series. Through the quest series, you learn to free yourself from your shackles: be it the organisations looking to control you, or even your own past and regrets.

A chorus of voices cries out for a hero, and she comes. She smiles. She nods. And she remains silent... But she too has a voice... I will be heard... Listen to my voice. Listen to your heartbeat.

DRK here has more in common with knight-errants. It's not really about debilitating your foes or breaking them. It's about finding your voice and living in accordance with your inner sense of justice. 'Sacrifice' is about giving up your self-imposed constraints and learning to live freely. It's not about dying in servitude to another's ideals.

"Serve... Save... Slave... Slay... I've sins aplenty, aye, but regrets? Not so much."

Grit and Tenacity are also important themes here. Dark Knights in FFXIV are often depicted as unyielding when fighting for what they believe in. Consider the following:

"So as I was saying, that heretic was fighting like a man possessed. Even after he took several wounds, he showed no sign of pain─though there was no mistaking the blood. As the fight wore on, it began to soak through his armor, spreading to every ilm of his body. But when it began to rise and envelop him as a mist, I realised it wasn't blood, but something dark and twisted..."

It's a bit of a shame that Blood Price doesn't quite live up to this description.

FFXIV's lore takes us down a very different path from the journey made in FFIV. Where others are bound by their oaths to serve corrupt institutions and tyrants, Dark Knights are free to aid and protect those that they care about. Not because they're asked to, obliged to, or required to, but because they want to. It's a journey to find yourself, and free yourself.

After all...

"Justice deserves no less."