Bungie didn't make the dreaming city or shattered throne. It was made by an Activision studio called Vicarious Visions. It's highly unlikely bungie will ever revisit any content from Warmind-to-Forsaken, because, flatout, they probably wouldn't know where to start.. and if there ever were triggers set for last year's main story to advance past it's time, bungie probably removed or broke it. It's way more likely there never was anything ever planned because that would mean closing a story arch, and we all know how they rely on cliffhanger endings to create the illusion of suspense, because their writing is amatuer level gibberish.