Im sorry, even in this day and age where the Soviet Union has been defeated for over 20 years, there is no way Hollywood would make a communist Superman movie. Not going to happen, though it is doable.
Kingdom Come, while logistically impossible with its huge cast, would be a badass movie. I would even go so far as to say that if DC didnt change continuity every 5 seconds I could accept that as a actual future DC story instead of an alternate dimension story.
That being said, since those movies are undoable lets focus on a future DC story that is doable, has a story that alot of people know, and could even begin a new franchise. Batman Beyond. Think about it, after Bale's run is done and a few years go by people will want something new, fresh. This fits perfectly. The story has all the ingredients of a Batman movie, tragedy(although Terry only lost his dad and he and his dad wherent the closest to begin with), origin, action. You can still go for a realistic style like the Bale movies, but since its the future you can bring in all kinds of crazy tech. The Batsuit and old Bruce will also help speed up the whole, "hero trains and gathers resources" part the superhero movies tend to have since . Terry originally stole the suit and went out, so we can get right into Bat-action quickly. Then we can dial it back it bit and have Old Bruce teach him a bit then have a big climatic showdown.
Now tell me thats not only doable, but awesome.