Man, why does it need to be a massive game... please make less massive but equally impressive games for workers/parents/folks who want the same shit without the trudging around a, probably, meh open world.
I'm interested, but you say "open world" and say it's bigger than already big games, that's a turn off. You've already got retention issues in the medium as it is, why make things even bigger and bigger for the sake of it?