They were Dragon Killers in XI too (just the unholy ones). Which could very well be a reason/excuse to get a Wyvern/Dragon as Dragoon. Honestly though, if it means weakening the player to get a pet I would say no UNLESS:

1) Pet can get armor to make it stronger
2) It doesn't die in ten minutes from two magical attacks and has a 2 hour recast
3) It can be controlled instead of mimicking
4) Gains useful abilities to aid the Dragoon

But I wouldn't mind an ability that called down a Dragon for some big damage or something and has a big recast (10min or more depending on damage potency).

If there isn't a pet that comes with Dragoon then some moves I'd like to see:
1) Jumps (different kinds more than just the three that XI had)
2) Breaths (of all kinds that exceed past the basic elemental breaths)
3) Dragonheart (auto-reraise from tactics)
4) Dragon Killer trait

That being said, I'm a Dragoon at heart so I'd probably play the job anyway if they only gave us 1 more dmg per hit.