To be blunt they will never be able to add open world content with depth unless they overhaul how the treat the overworld in general.

-It's far too easy to get around
-Enemies are very bland and even at max level pose a laughable threat to even the most poorly geared players
-Unique things in the world don't happen outside of blue circles.
-Nothing special about monsters in the open world, no nifty AI, no tricks, no danger.

I'm gambling on the expansion taking a bit of a paradigm shift to how they look at the open world, they have a amazing world we should be exploring more often than running to and from the next FATE for our Atma farm.