I don't think there is a player on the tour who suffers more from drastic changes in confidence. She can use a whole a tournaments to build up enough confidence to have everything working well, then with in one point..she starts to question herself and everything falls apart. She puts on a good poker face, and continues with her game plan..but sometimes I feel this is more of a negative than a positive.
Her backhand has always been pretty bad. Before her comeback, she would drive through her bakchand, but was never able to produce the depth necessary to stay in the rally effectively. She has improved that a lot, and hits it more freely these days, even going for down the line winners!!!
Not sure what was going on in the Jankovic match, she seemed to be struggling with a shoulder injury or something, so that could be a reason for the RIDICULOUS amount of slicing.
Forehand is one of the best in the game when its working, one of the worst when its not. Again its all got to do with confidence, if she starts questioning herself, she loses racquet head speed and that results in a load of errors. When its working, she can produce awesome angles and push her oppenant further back behind the court because of the huge amounts of top spin. Volleys are pretty similar, she is good coming into the net and generally sets up the point really well. Once she is there, she can look a little bit lost if she is having a bad day, if shes playing well she seems to get all of them back.
She has every serve in the book. Shame she seems to go for the kick a lot more than she should. It works on slower surfaces, but I agree she needs to go for the flatter serve and slice serve more often.
Biggest problem is her mind. I think thats pretty much always going to be a problem. Still, when she is playing remotely well, it is always refreshing watching a player like Sam who is capable of doing more than staying on the baseline. Hopefully she doesn't remember this last result for too long, and can comeback fresh in Miami. (still has doubles to go though)