It's good enough sized to be fit for another Pygmy Hippo exhibit. Maybe then they can afford to merge the current two exhibits together to form one.Unless there are imports - there won't be any Bongo for Taronga to hold.... I'd like to see that space given to the Pygmy Hippos maybe with another pool at the far end of that exhibit.
Concerning Gung's habitat I personally don't see any major changes being made to it going forward. The train will still run until the new sky safari ride is complete which is still likely years away. There were talks of using this area as a 'third' sky safari stop although I'm not aware of how far into the plans this got.
I also recall hearing initial plans about the sky safari receiving a third stop at the opposite end of the zoo, however from the looks of it with recent announcements, this is no longer on the cards. Instead, a new route is being planned down to the bottom - I wonder whether any plans for a gorilla expansion may have any ruling towards this.