The biggest problem with the idea of a new gatherer is what do they actually bring to the table? You're basically just asking for an easier/lazier way to gather materials we already have access to. There's not really any great need to add more new materials to justify it, which would be working in the wrong direction besides. There's not really any room to justify uses for any hypothetical new materials; new crafts would need to be added to justify adding new materials to justify adding a new class, and it'd all just be arbitrary and meaningless.

And then you got things like where does it start? At level 1 like the others, tacked on somewhere in ARR city states? What about all the new leves they'd have to design for them? What happens when players start asking "Why doesn't this one have Supra/Lucis tools?" How do you integrate it into previous level cap gathering and crafting vis a vis timed node materials? How does it fit into Diadem and Ishgard Restoration?

In conclusion, that's an awful lot of additional consideration, and work, all because some players don't want to spend 20 minutes on DoW farming mats, they'd rather do it on DoL.