Mao has been far worse at Worlds than at 4CC the last 2 years but each time there were reasons behind it. In 2011 it was the earthquake that broke her focus, then in 2012 as far as I can tell it was from her mother's death affecting her mindset. She insisted on trying the 3A before it was ready and tired herself out practicing it (she went for it 40 something times in practice and didn't land it once).
Carolina seems far better at holding herself together these days; adding her old content back gradually seems to have been the right choice. We haven't seen anything like 2009 worlds or 2010 Olympics from her in ages.
I want to see how Mao fairs this time, because she doesn't have anything to distract her at this Worlds. She'll be out to beat her rival and earn back her title.
I admit that Carolina has been more consistent lately, but she really didn't have anyone to challenge her. The title was hers to lose last year but this time she'll have to fight for it.