If it winds up to be similar to the likes of Super Mario 64, Sunshine, Galaxy, and so forth, I could tell many of us would find ourselves enjoying our time playing, and quite a bit at that.
I'd imagine them to give us options to choose what Pokémon we'd like to roam with, and as for quests, they'd likely resemble things from Mystery Dungeon and whatnot. After defeating some opposing Pokémon on our journey, we could perhaps gain experience (just like in main series titles), and evolve as time moves forward.
I'm not sure about others, but I would personally like it more if they were to make this game available to a home console than handheld, due to graphic reasons. I wouldn't mind latter, but would definitely like them to try former first.