To further add on my previous post, it is a bad game-design idea to fix the problems of a certain class through certain specific items for three main basic reasons:
  1. You will have to obtain that item (and possibly it could be even hard, and until you do your class will remain "broken")
  2. You will limit the freedom of the player which will be "bound" to equip certain items to "fix" their class
  3. As game proceeds and stats are raised even further, SE will need to release even better fixing items

This cannot work on the long run.
The problem of pet jobs are different and reach a very different scale for different jobs, but I think they could be generalized in two different issues:


Pet Survivability
You cannot directly heal pets, but are limited by specific abilities that only the master can use and that have certain cooldowns. Also pets do not have their own gear, and "Pet: ..." gear the master can equip is obviously (and rightfully) limited.
This makes survivability of pets particularly hard in certain fights.


Pet scaling
Unlike other classes, the damage of pet classes is split between master and pet.
When another class receives a buff that boosts its ouput, this boost affects the 100% of that class' possible damage output.
When a pet class receives the same buff, only a smaller % of its overall damage is boosted (the master's).
The same happens with gear.
As new gear is released, 100% of another class' damage is boosted, while only a % of a pet job class damage is boosted (the master's), making the gap between master and pet even stronger and making the previous issue even more influent.


Possible Solutions:

Pet Survivability: Cannot make pets too resistant to overall damage, or it could create some annoying situations (especially for BST). They should instead add a job trait that makes so pets receive reduced damage from AoE moves that do hit them, but that didn't directly target them or their master.
The amount of reduction should be balanced, not too minimal, not too strong of course, and could be furtherly enhanced by specific equipment.

Pet Scaling: This probably isn't a big issue for SMN (they have other issues), and it's a minimal factor for DRG, but it is very crucial for BST and PUP. It's also the "norm" in practically almost every other MMO.
This scaling should be balanced as well. Cannot make it too big or you would make "Pet: ..." gear useless.
It has to be a small bonus that scales with some of the master's stats and according to a specific formula, grats specific dynamic bonuses to the pet.
This way "Pet: ..." gear will still be relevant/interesting, but it would be an additional option for specific builds to suit specific situations or player's tastes and styles. It would not be something "required" to fix your class.


If a class has issues and needs a fix, you need to do it through job traits or job abilities, not through specific equipment that forces the player to gather such item and binds them to use it.
Gear should be something to be looking at to make your class stronger or more "special", not something to "fix" your class.