If they did it right, it could destroy WoW.
Just imagine getting your first pokémon, going around in the wilds together with other trainers, and then you find a pokémon and the gameplay becomes pokémon stadium-like and you fight it and then catch it if you can. Some things like the dungeons where you get Zapdos and Lugia and maybe fight team rocket should be instanced, and really difficult so that not everyone can have Zapdos or Lugia. There should be no NPC trainers (maybe only a few like gym leaders) All trainer battles should be with real people and would work similar to duels in WoW and play like pokémon stadium. Other trainers should be able to watch other people's pokémon battles. There should be a real pokémon legua organized with real players in game. People should be able to trade pokémon.
I could go on forever.
I LOVE ICELAND!
