I thought the judges were far too hard on Katie last week, and it probably affected her confidence for this week. They are comparing her with contestants who have more dance training, and therefore more muscle and a sure grasp of certain technical challenges like spins, etc...
I have taken a look at Lesley Garret and other partners with whom Anton was paired, and I don't think any looked better than Katie, to be honest. The standard has risen, in my opinion, and more and more of the contestants are starting at such a high level that it is difficult for people like Katie, who has genuine potential, to measure up. She just needs to strengthen up her muscles, keep her morale level high, and possibly be given routines which enable her to concentrate on improving her basic technique, rather than showy stuff which doesn't always come off. I also feel that a slightly lower heel might help her balance and master the steps in the fast Latin dances.
Whether or not Anton is responsible, I think he needs to get some Latin tuition himself, so he has a better grasp of basics, common faults and how to correct them. He should ask one of the eliminated women like Ola to assist with the tuition of Latin basics.