Unsure about all the negative thumbs here, but I would support the idea. Running around an open world with Pokemon in their natural habitats, interacting with each other with realistic AI. Rares could roam and be genuinely difficult to catch, and the player could play as the pokemon they use in battle.

It could be a genuinely amazing idea if handled properly. However, the reaction to your post shows that most people can't think outside of the very tiny box of what already exists.