With the way how zones are set up to it's own thing I doubt they'd do this. Some zones already get congested and start lagging if they were to make it open world they'd have to pretty much redo the game which is something I don't see happening.

What I would like to be seen are the zones being expanded on. For example the areas between the zones (ie the zones between east shroud and south shroud http://i.imgur.com/jbn1iKQ.jpg the white zone). If they were to redo everything to be able to make it an open world then we'd probably lose out on an expansion.