To me it seems as though they decided at the last minute to change direction I don't know why, only they know that. As a result they had to pull content very crudely out of the game at the last minute. The PS3 release was confirmed as being finished in Oct/Nov but they still decided to hold it back for 6 months from launch to give themselves time to get the game and systems running properly with the new direction. They new they were going to have a bad launch I just think they underestimated how bad the backlash would be.

They got panned in the reviews and they were losing players at an alarming rate, they removed the player search feature as people were publishing the rapidly declining populations on the servers. SE had to act like they were taking this seriously so Tanaka stepped down. On a side note it is not a NEW dev team it is the same one with extra staff now to help get FFXIV back on track, even Tanaka is still on the dev team.

The obvious big change they needed to make was the battle system as it would have probably worked with the original vision but they obviously don't think it will with this one. Until the battle system is done their hands are tied really as it is a huge part of the game. They also have to find new ways for crafters and gatherers to level which will probably come with Companies.

I believe SE had a lot of content ready for the game but pulled it at launch while they figured out what they were going to do and also so we didn't get 2 far ahead of the PS3 players. Also it would need readjusting and balancing for the new systems. The evidence is all around you as you wander Eorzea tunnels blocked with invisible wall's, parts of the main cities we can not access, airship's, chocobo's. These were not things that were not finished, they were things they purposely pulled to hold back.

Hopefully once the battle system is in and complete we will start to see them add content rapidly, either that or maybe they will try and hold as much as they can for the PS3 release.