Yeah, but Ash's voice was rather high during the late Kanto/Orange/early Johto parts of the show. I noticed Veronica purposely made Ash's voice deeper once Hoenn began, which was good because it reflected his maturity that saga since he stopped being that clueless kid he was before.
As for Sarah, I recently bought the Battle Frontier DVD boxsets so I was watching through that season again, and my god Sarah really has improved. I honestly forgot how bad her Ash voice was for like the first 10 or so BF episodes, it reminded me why everyone complained back then. Everyone elses new voices were great, except for maybe Max. At some point in mid-BF it improved, I think it was right at the point Grovyle evolved that Sarah's voice improved, and it got better through DP to where its at now. While I agree Veronica was better, I do think Sarah deserves credit where it is due. Its pretty admirable, I'd say how much she improved.
I dunno, I think it was also her voice that season. I don't know if it was the same as in the Japanese version, but Misty's voice sounded way too calm and reserved in Johto, and as a result it made the character sound really boring. Part of it was the writers to blame, the other part was the way Lilis made her sound so monotone. I don't know, maybe it is just me.