They are releasing so many NPCs to give players latitude in choosing which NPCs to use.
Since Trusts are roughly equivalent in power, it is not unheard of to make choices in the name of "fun" or personal preference.
What you are proposing removes that element of choice and fun, and leaves every single adventurer in Vana'diel with Prishe out or a 49 level penalty to their Trust's subjob.
I appreciate your enthusiasm, but this is one case where I think balance needs to trump lore.
