Sounds like a really interesting concept. would there be any sort of story or would it just be wandering around catching and battling? Story is pretty important for pokemon games usually, but there's always a bit of a thrill when you know what you're finding is essentially random and others haven't just walked the same path before you. I would like to think there would be towns generated too, with a chance of gyms in them? because of the open nature of the world, the gyms could either be scaled to the player (so they can fight them the moment they get there) or have them have an independent level, so that if a player finds a gym that's too tough for them, they can adventure around some more, train up, fight some weaker gyms, and come back when they are strong. this could also apply to dangerous areas/areas with legendaries maybe? just spitballing ideas here.