It depends how detailed and rich that open world is. I don't care if it's a vast open landscape consisting of a hundred thousand square miles if it's just empty landscape. I'd much rather play in a smaller space which has been carefully designed and full of interesting detail. I also dislike the repetitive busywork tasks dotted around the map that seem to go hand in hand with this genre too, such as Ubisoft's apparent fixation with having you climb towers.

I agree with what Fox said about separate maps being the distinction in whether or not a game can be classed as open world. And you know what? I think the likes of FFX were better for it, as you had some really varied and interesting locations to explore.