Necromancer is not a job you often see in a Final Fantasy.

We first need to identify its... Identity

It appeared in V with the additionnal content in the remakes and... As an ennemy.

They use Dark Arts such as Drain Touch, Dark Flare, Deep Freeze, Hellwind and so on. The problem I can already see, is that these abilities fits on Dark Knight and Black mage.
The other problem I see is that they use Death and Zombie. Death is a Blue Spell, Zombie can't exist as a usable spell for obvious reasons.

Another problem is tied to the lore and the world. You're the Warrior of light fightning against evil and for the weak, yet you summon the corpse of the deceased...?

In short, Necromancer should actually be a "Void mage", it's a recurrent theme and different enough from Black Mage/DRK. You could exploit existing spells such as Meteor or Black Hole. On top of that, it's already tied with Necromancy. Neat!

Then you have to look at the design.

You mainly want to keep the Dark Arts theme while not making the job a duplicate of Dark Knight and Black mage.
The other thing(s) you want to avoid are pets. They're badly designed or badly implemented, either a glorified dot (MCH, DRK) or a laggy extension of your character (SMN/SCH).
According to your design, you don't interact with a pet, you just let it do its own thing until it dies and they gives you resources.

You are going to use Dots that deals damage on their own. You are going to summon skeletons that deals damage on their own. To fuel a gauge that summons a bigger skeleton to deal damage on its own. I'm not exactly sure if XIV players wants to play cookie clicker.

"Bone-magic" also sounds... off. Unless it's Undertale, but doesn't fit in XIV. I don't think there was ever use of Bones as magic in past FF titles.

Limited play
Forget that.
Blue mage reception was so terrible they canceled/post-poned plans to implement Beast Master as a limited job.
Plus you'd have to design and balance all of this just for fluff. Too much resources to spend in a single job, you'd have to select the specific monsters to be used as pet, you'd have to manage a specific IA for that, unless you want it to aggro any monsters within range.

Overrall
It's a cool suggestion but it's more a design you want and not a design that would fit in the game, that the community would actually want.
One of its problem is that it takes a lot from existing jobs: Pets and dots (SMN), Life Drain and Dark Arts (DRK). Bone magic is unique, but there is no such thing as "Bone element". Ice or Void would fit much more, but I don't see how the WoL could actually use the Void, maybe like Exdeath to empower its attacks.
The first task when you design something for a game, is to ask yourself how much resources it will need and if it is feasible in a reasonable amount of time. The design also has to make sense in the World and you can't use the excuse "It's magic".