I'm gonna throw out some ideas for new Pokewalker areas because I really want a new Pokéwalker

LUSH COUNTRYSIDE
> Group C: Bunnelby, Wooloo
> Group B: Smoliv, Rookidee
> Group A: Applin, Tandemaus
GLOOMY FOREST
> Group C: Nickit, Phantump
> Group B: Impidimp, Hatenna
> Group C: Indeedee (Male), Indeedee (Female)
SANDY SHORELINE
> Group C: Wiglett, Pincurchin
> Group B: Wattrel, Sandygast
> Group A: Pyukumuku, Bombirdier
CRYSTAL CAVE
> Group C: Rolycoly, Nacli
> Group B: Mawile, Sableye
> Group A: Noibat, Gible
DESERT VALLEY
> Group C: Silcobra, Helioptile
> Group B: ???
> Group A: Falinks, ???
HAUNTED MANOR
> Group C: Shuppet, Sinistea (Phony Form)
> Group B: Kelfki, Honedge
> Group A: Mimikyu, Sinistea (Antique Form)
LOST TROPICS
> Group C: Pikipek, Slakoth
> Group B: Tropius, Archen
> Group A: Jangmo-o, Tyrunt
LOST ARCTIC
> Group C: Bergmite, Cetoddle
> Group B: Eiscue, Spheal
> Group A: Frigibax, Amaura