i feel that mounts are for customation, and that they all should not have gameplay advantages, perhaps suggest to stefan that the player be able to get the first original horse at balamb, and all mounts being able to carry two people, and the prices just be spread,
its how its meant to be, you shouldn't need to pay for actual gameplay advantages, the payment is for vanity and customization, look at shields and swords and bodys and heads and hats and bombs, they all do the same thing, even without them your at no disadvantage.
same should be with mounts.