I like it!

What if, instead of it being a new job, it instead requires a breadth of activities that involve all kinds of jobs -- combat, gathering, and crafting? For example, maybe the quest chain involving research into Amdapor sends you to play the dungeons related to that. You get fragments of an ancient artifact, and then you have to play a crafting job to restore or reassemble the artifact (maybe a stone tablet or something). The completed artifact may hint at a location or serve as some kind of crude map, so you go where it indicates on a gathering job and search for something to excavate. Or you could even go back into dungeons as a gatherer in Explorer Mode, and follow the clues to find what you're looking for.

There could also be an aspect to it that has you becoming more familiar with the current state of the world, and has you do local FATEs or complete X amount of side quests. There are a ridiculous amount of side quests in this game, but as I've been going through the MSQ I feel like there is no need to actually do any of them, at least for leveling purposes. This could be an incentive for players to actually do some side quests and learn about local lore, and perhaps an excuse to dramatically bump the quest xp so we can level alt jobs during our Historian journey.