Which is exactly how much you'd be complaining if Dragoons underperformed versus other jobs. And, having a wyvern around is the perfect way to get that ball rolling.
Here's a simplified explanation of comparing a Warrior to a Dragoon:
A) Overpowered Dragoon
Dragoon 100% of Warrior damage
Wyvern 30% of Warrior damage
- Obviously this is ridiculously in favor of Dragoons. Not only does the Dragoon alone do as much damage as a Warrior, but the Wyvern puts it over the top. No other damage dealing job would be able to compete with this. Both the dragoon and wyvern combined can't cause more damage than a Warrior would.
B) Equal Damage Dragoon
Dragoon 70% of Warrior Damage
Wyvern 30% of Warrior Damage
This seems more equitable. Dragoons and Wyverns account for approximately 100% of the damage Warriors can do. But there's a problem. Because hate is split between Dragoon and Wyvern, Dragoons can spam more abilities without stealing hate. Warriors are accountable for 100% of the enmity and have to hold back. This means that Dragoons will continue to have the performance advantage over Warriors even if their damage capabilities are theoretically identical.
C) Underpowered Dragoon
Dragoon 60% of Warrior Damage
Wyvern 30% of Warrior Damage
Because Warriors take 100% enmity for all their actions, but Dragoons only take a partial amount (because it's split over two beings) they can spam more abilities without concern of stealing hate. So, it may seem fair to lessen the amount of damage Dragoons can do overall to "balance it out." Unfortunately, this means in situations where hate isn't a concern, like short fights, that Dragoons will underperform versus other damage dealing jobs and sit on the sidelines unwanted.
So you see, even as a simple damage versus enmity problem, it's already hard to figure out where to draw the line. This glosses over all sorts of other issues like damage absorption, healing pets, recovering dead wyverns, kiting, pet equipment taking up valuable damage equipment slots.
And because it's so hard to foresee just how balanced a pet job would be, it's more than likely that the developers will err on the side of underpowering Dragoons than be forced to perform a heartbreaking nerf to an overpowered job. It would be just like FFXI all over again with Dragoons struggling for legitimacy from day 1.
And that's a shame, because Dragoons have a great legacy in Final Fantasy, one that didn't involve using wyvern sidekicks.