Ash should have used all of his strongest Pokemon in the battle. I don't know why Charizard never returned. Although it wouldn't have mattered anyway. Seeing how that Takuto is a legendary noob, Ash would have lost anyway. Did Takuto also have a Lugia or Deoxys as well. Heck, I wouldn't be surprised if Mewtwo pooped out of his Pokeball. Using a legendary trainer to rush the ending wasn't the best idea IMO.