Chocobo mounts should be in the game at release, period.

They had 5 years to develop the game, even when they were still creating Crystal Tools, they would have already started the planning and conceptual designs of the game, content creation like story writing etc, it's not like they can't do anything when crystal tools is still incomplete.

So yes, it was 5 years of development, but SE still manage to release a half-baked(or quarter-baked) game with barely any content, how crazy is that.