I'm not too sure about the Magma admins' redesigns, but I can see why they happened. Looking at their old sprites, Tabitha and Courtney looked pretty darn similar to the grunts. I liked Courtney's skirt, though, wish they had kept that instead of giving her those shorts.
Team Aqua looks great, as everyone seems to agree. I wasn't expecting Shelly to change that much, but she still looks cool and she fits Aqua's theme a bit more now, I guess.
Since the gym leaders might be getting major redesigns, I just really hope that Game Freak doesn't pull a Skyla with Winona. She looks fine as is and I feel like giving her a skimpy outfit like most female characters in this series have would take away some of her charm.