Everything I wrote in the original post dismisses what you just said though.......
It is only a legend that Arceus created Sinnoh, and possibly the entire Pokemon world. It is complete legend. Thereby, it in no way created the entire universe. It did not create humans. It does not have the power of a star, as you have said. It is no more than an ancient Pokemon, similar to Rayquaza, Groudon, and Kyogre. It is extremely powerful, but you, and so many others, have placed this mystic around it because it is rumored to have created the Pokemon world. Again, I repeat, having God-like status does not make you unbeatable. When it comes down to tic for tac, Mewtwo has the advantage in sheer power and intellect, as has been demonstrated in the movies, anime, and books. The thing I have noticed with so many of these ancient Pokemon storylines is that they do not seem to be very cunning. They have their primal instincts, ex. defend land, ocean, sky, and will battle brutally for their cause, but they are in no way what I would call intellectual. Mewtwo on the other hand is intellectual and possesses unimaginable power. I don't think you can comprehend how powerful and unlimited Mewtwo's Psychic abilities are. If you're going to talk about giving Arceus a Dark Plate, aka an outside advantage, then you would have to compensate an advantage for Mewtwo as well. Arceus untouched is merely a Normal type. But we shouldn't even have to get into Type matchups, seeing how in Mewtwo Strikes Back, Pikachu 1 hit KO'd a Golem with Thunder Shock. Think about that. Now don't even try and tell me Mewtwo would have a problem in an anime setting with getting around a Dark Plate. You're last sentence baffles me. I just watched Mewtwo Stikes Back for the first time in years a few hours ago, so I am completely fresh on everything that happened. You do remember that Mewtwo stopped the fighting (that he induced by his own telepathic powers) by his own will, once he saw the sacrifice Ash had made? You do realize he was preventing around 100 Pokemon from having the ability to use Special Attacks, telepathically, to prove that his clones were, in fact, superior, all the while fighting Mew (who in the anime is also considered extremely strong)? It is of no question in my mind that had Mewtwo not had a change of heart he would be ruling the Pokemon world right now. But that was the point. Everything this franchise has ever done, began with Mew and Mewtwo. It was about him finding his place in the world he was thrust into. The ending was about his redemption. He stopped the fight, no one ever stopped him.