I disagree.
I've seen all the Battle Frontier episodes they've showed this far, and in my opinion, Sarah (Ash's new VA) has not improved as much as I've expected.
There was only one episode where her emotion problem seemed like it was better, and that was with the episode "Talking A Good Game".
Unfortunately, that didn't last long, cause with the next episode "Second Time's The Charm", Sarah's Ash voice was exactly the same as it had always been - with very little emotion.
And I don't know about you guys, but I'm hating this. The fact that the main character, Ash, doesn't have any emotion is just killing me. It's even worse because Ash happens to be my favorite character.
I've said this many times before (in the New VA Discussion thread on Bulbagarden), but I still think Sarah Natochenny isn't the right person to voice Ash. I'd much rather have someone experienced voicing the main character of Pokemon, someone like Veronica Taylor. She knew exactly what made Ash "come to life", and I loved her Ash voice. The way she portrayed Ash was great.
Anyway, on another note, I'd like to say that while Sarah is very good at doing the voices for important female characters (Frontier Brains, Gym Leaders, etc), and female characters of the day, she is NOT good at doing Ash's voice.