It's practically impossible to teach being a 'great competitor'. You either got it or you don't and I think that's an issue for not only the US ladies, but the Russian ladies as well.
CoP might have something to do with it. Tara, Sarah and Michelle didn't have the burden of competing under CoP (Michelle dealt with it once at '05 Worlds and she was off the podium); worrying whether they were going to be 1/4 turn short on a jump, how many positions they could manage in a spin, how many revs they've achieved might have distracted them to the point of being inconsistent. We will never know.
Ashley's '13 SA mark is above any of her marks from the '12 - '13 season.
Gracie's lower GP mark is still better than the higher of her 2 GP marks from the '12 - '13 season.
Christina's SC mark is about even w/ her best GP mark from '12 SA last season, and her SP score at SC was quite high.
Courtney and Samantha are new to the Senior level and have no Senior cred, but are doing quite well score-wise
Agnes and Mirai really need to step up their games, though.
And, I just want to say that US ladies historically are pretty good at playing catch-up as the season progresses.