What could DRK have learned from FFXI?

[TouchandFeel]

And for the record, in FF III, it's not a Dark Knight as in 暗黒騎士 but a Mystic Knight まけんし. It was only translated as Dark Knight in the DS remake...where it gained Souleater.

まけんし (ph. Ma-ken-shi) does not translate to "Mystic Knight".

Kenshi is literally swordsman/fencer and Ma is a descriptor that basically means "supernatural with a dark, ominous or scary connotation" or can at times mean conceptually "cursed" or "demonic (in a more Japanese sense)". It's something that is hard to describe or perfectly translate into English. So saying that it was "Dark Swordsman", "Dark Fencer" or something along those lines is not far off and closer conceptually than "Mystic Knight", where "Dark" is more the conceptual idea, like in dark forces or dark magic, as opposed to the literal like darkness in a dark room.
Also just a note, the kanji version of the name is used/referenced here and there for Makenshi as well (魔 剣士) and not just the Romaji (まけんし).

In regard to the job translated to Mystic Knight that came later, 魔法剣士 (ph. Ma-hou-ken-shi), that translation is much more fitting.
Mahou translates to magic, but specifically the Western idea of magic like wizards and the like. So Mahoukenshi means Magic Swordsman, Mystic Swordsman, Magic Fencer, etc. and Mystic Knight is not far off.

The later more literal name given for Dark Knight is exactly that, literal. 暗黒騎士 (ph. An-ko-ku-ki-shi), with ankoku translating to literal darkness, as in the lack or absence of light, and kishi meaning basically "knight", 騎 - this kanji (ki) refers to equestrian/having to do with riding a horse and 士 (shi) refers to a person of skill, expertise or of standing just like in kenshi (剣士) <-- see the character at the end there. So basically a person skilled in riding a horse which conceptually means basically a cavalry person which means a knight.

In essence the later name used for Dark Knight was an evolution of the name used in the Famicom version of FF3, taking the idea of a Dark Swordsman and going super literal to fit the narrative of FF4 where Cecil is literally a knight in the service of the kingdom of Baron.
So Makenshi (魔 剣士) is the precursor to Ankokukishi (暗黒騎士) and the foundational concept is the same.

I hope that from now on the "Makenshi means Mystic Knight"/"It was called Mystic Knight in FF3" thing is appropriately binned and I never have to go over this explanation again.

P.S. And before anybody brings it up, although the kanji for ma (魔) appears in mahou (魔法), the darker connotations of ma do not carry over to mahou as mahou is very specific in being the Japanese idea of "Western magic" which doesn't have any good/bad/dark/light connotations inherent to it.