Necromancer was one of the strongest jobs in FFVa lol, I don't think that qualifies as crappy unless you consider Blue Mage crappy since with the exception of a few spells, it was less powerful than even Red Mage.

Here's Necromancy history in even FFXI:

-During the Crystal War there was a sect of Necromancers whom were banished to the Phomniua Aquaducts as Necromancy, much like Summoning were sooner outlawed and deemed too dark of arts.
-Enaremand wants you to find one of said Necromancers to attach a spirit to his mannequin, Aisha which you then complete the quest and end up fighting Aisha, whom is a very troubled soul given the way she fights you.
-The same technique is given to Puppetmasters for attaching souls to Automata, which in essence, makes Puppetmasters Necromancer apprentices as you're controlling a newly attached spirit to a doll.

So it wasn't just 'mentioned' in prior FF games (with Va and XI being major examples) it was actually pretty rooted in history in the previous FF online game.

So while true, Necromancy isn't linked to FF like say Black Mage is, but it is something that's been found in FF before.