I really doubt mounted combat will be implemented anytime soon. Probably not until sometime next year, and only in new regions. I don't want my chocobo do die! It should be like Super Mario Bro 3 where when Yoshi got hit he would blink and run away :P

Nah, just normal mounts for transportation will be nice at first. Then when the Garlean Empire zone is released we could have some cool mech mounts