Turtok said:
Professor Oak, while an awesome character, is not omnipotent and had to logically have sources for the information listed in the PokéDex, and while some information, such as Squirtle's back swelling and hardening into a shell at birth, is easily researchable and able to be documented, something such as the creation or shaping of the universe cannot, and Oak likely got his info from legends regarding Arceus. Same goes for the extent of power Jirachi, Palkia and Dialga have, I agree, they are highly powerful but I'd bet your wish would be beyond Jirachi's power, and that Team Galactic over-estimated the Time/Space Dragon's powers and would've been destroyed had Diamond/Pearl not interfered.
You seem to question the power of the legendaries in general.... You question Arceus' role in history, the powers of Jirachi, and even Palkia and Dialga.
I think we have something in common. We question Arceus being god. But unlike you, I don't question the powers of the legendaries in general. I just accept it because of the powers they display in the games and anime. For me, it's not questionable since that's what Gamefreak intended to..... (but since they are legends, you have a point. But in the case of Jirachi, we have witnessed his powers during his own movie, so it is unquestionable).
Pokedex is a hi-tech encyclopedia that records any information, if not all, about the Pokemon you have seen or caught. That's why the Pokedex can tell why Squirtle's like that, and why Charmander needs to keep his flames lit, etc.... We don't know how hi-tech the Pokedex is, and it can record even trivial informations, including their history. Prof. Oak gave the Pokedex in a "blank" state, meaning it's really blank and nothing is written in there, but equipped with hi-tech gadgets that can examine a Pokemon with precise informations. It's up to the trainer to complete it.
That means it is not the professor's research the informations that are recorded in the Dex. It's the Pokedex that you can blame to when the Pokedex states "A legend states that Jirachi will make true
any wish that is written on the notes attached to head when it awakens. If this Pokémon senses danger, it will fight without awakening." or "Arceus is described in mythology as the Pokémon that shaped the universe with its 1000 arms". The technology in the current era of the Pokeverse is amazing that it can tell trivial informations by just examining the Pokemon very well....
BUT, I don't believe Arceus is god, because it is fanmade proclamation, and no official claims state that Arceus is really a god of Pokemon, when even Slowpoke is even deified by ancient people of the Pokemon world. Arceus is only a creator, but not as far as Arceus created all Pokemons, that Arceus filled the oceans and teared the continents, or even Arceus is the most superior Pokemon of all. It's a cult, I tell you, a CULT !!!
There will be a 5th gen, and Arceus is not an obstacle for that.