Yes, it was definitely a little different during the early Kanto, not just because Veronica was still fitting in her role, but the voice directors were still deciding how they wanted it. I agree with Silver though, it somehow makes sense character-wise. TRio took some time as well. Rachael had Misty more or less figured out from the start. Brock's wasn't quite himself until after his debut episode, but he was of course a super serious gym leader until leaving with Ash, allowing Eric to open him up a bit more.
I am the current leader of Save Our Voice Actors, a Pokemon fan group supporting the voice actors in the anime dubbed by 4Kids (seasons 1-8). Our goal is to provide The Pokemon Company international with encouraging feedback in support of returning the main cast members. If you're interested, please visit us at facebook.com/saveourvoiceactors