Absolutely. I think it comes down to experience. Erika Jo comes from a musical family. Her dad had his own band. She's been performing for 13 years and has fronted her own band. Experience does make a difference.
I think silent_jonny is right that Carrie is a bit frightened. If she could learn to relax and have fun with her music, that would translate to the audience.
I know she needs to have fun but in all honesty if I had to face Simon after a performance, I believe I would soil my pants. :) I love his honesty with the performers but if I were one of the performers I might be singing a different tune. I imagine it is hard to be critiqued every week. Another reason I like Bo so much, he takes everything said to him in a good manner. Even when Simon said something negative, he said thank you and will smile. All the ones I have ever truly liked have been able to take the criticism with a good attitude. (Clay, Ruben, LaToya.)