When I was younger and trying to imagine bigger Zelda games on future consoles, I would always simply think about a larger Hyrule, where you could go anywhere-- no boundaries. When I got Ocarina of Time, I loved it, but I hated how restricted it felt. You had a big, pretty empty Hyrule Field, there was no wide open forest you could actually explore, just a series of logs and square rooms interconnected by said logs, Lake Hylia was a giant pond instead of a large network of streams and larger, uneven bodies of water, etc. Great game, but the environments, outside of the great dungeons, were pretty limited in scope. It disappointed me in that way.
I don't like the type of open world games like GTA and inFamous, I just find them exceedingly boring, but it's the way that they're set up, the way that goals are given to you and how you have to travel to waypoints and shit. A bigger Hyrule without boundaries and dynamic environments wouldn't necessarily be the same thing-- and honestly-- it would probably be fucking god-like.