How long do mounts take to add?

[Elexia]

'If they didn't have to redo things"? What do you mean? Chocobos should have been implemented from the very beginning, even before they realized they would have to redo things.

5 years.

2. It's well known that the CT development was the majority of the 5 years the game was spent in development. XIII's PS3 redesign was completed around the time the CT became stable.

If you recall:

"Chocobos time around will be used for something different"

Therefore that "something different" wasn't even likely designed given the rushed nature of this game. The overhauls they likely retracted that design decision (much like they seemed to with Hamlet Defense.) A lot of the planned updates they seemed to have retracted in order to fix this game.