Was discussing some of the new job conversations with a friend on a MU* and had an idea on introducing new jobs without messing with the lore too much, and this was mostly inspired by Arcanist, in that, with this concept, each of the new jobs that hasn't been mentioned before is an alternate soulstone, much like Arcanist can go either a nuking role with Summoner or a healing role with Scholar. One rough idea would be

Marauder->
Warrior: Tank (Requirements: Marauder/Gladiator)
Dark Knight: Tank/DD hybrid (Marauder/Thaumaturge)
Pugilist->
Monk: pure DD (Pugilist/Lancer)
Dancer: DD/Support (Pugilist/Archer)
Archer->
Bard: Support (Archer/Pugilist)
Ranger: Ranged DD (Archer/Lancer)
Gladiator->
Paladin: Tank (Gladiator/Conjurer)
Magic Knight: DD/Support (Gladiator/Thaumaturge)
Lancer->
Dragoon: DD (Lancer/Marauder)
?