This is why I don't expect Dark Knight to come off Gladiator. Marauder or Lancer seems much more likely, probably Marauder. They can just do the same thing as Scholar and Summoner, except while Summoner and Scholar still both use Books, Warrior and Dark Knight can end up using Axes and Scythes/Great Swords. It certainly wouldn't be impossible, but it would be some extra work, Summoner and Scholar both use the same casting animations, Warrior and Dark Knight would probably end up having slightly different ones, though Scythes might be close enough to Axes to ignore that. They could even just leave Dark Knight with Axes, just give them more of a headsman feel.
Marauder 30/Thaumaturge 15 + Lancer works pretty much perfectly for Dark Knight though. The only issue is people not getting the weapon they want (us Bards play our non-existent tiny violins for you). They could even leave in the "Increase Enmity" from Marauders combo and just work it into the Job, having it trade off Enmity to boost magic damage or something, while also giving it access to Fire/Blizzard from Thaumaturge similar to how Scholar gets Clerics Stance.
