I see both sides, from DRG being my first 75 in FFXI, i enjoyed having my bird along with me but in end game as someone said earlier it was very weak and a burdon to others trying see things past this pet bird blocking there view it must have been frustrating.
And in a new game in a new MMO that is what XIV is at the end of them day it think we as Lancer-drg should get the choice and those who choose to have a pet have a disadvantage of lowered damage and lowered hp due to the spiritual link between you and your wyvern, others who choose not to have it could benefit from stronger damage higher HP and be great DD.
Both would have their uses and as in having your bird could be good support for those solo situations, and your character could have items specific job quest obtained items that trigger certain breaths when you use a certain ability and or weapons skill either that or only give your wyvern 2 breaths fire and healing.
not having a wyvern would have the benefit of being a great DD.
(i'm secretly wanting the purple AF to come to XIV) lol