By the end of Revolutions, as signified through Sati, machines discovered the concept of love. The Matrix is saved, people are free to leave or stay and overall peace between machines and humanity is achieved. The peace is supposed to last "as long as it can".
So they should just continue the story and explore what happens to the Matrix. What caused crumbling of those achievements. How things evolved. Since the movie is still called "The Matrix", it should play a key role. I wouldn't want more false bottoms like Matrix within Matrix. In the end, how will the machines sustain it, considering that they orchestrated the plan to subdue the desire of human to revolt. If there's no reason to revolt, they can't keep them enslaved. What if there's mass disconnect or whatever... There are so many possibilities. What if machines society shattered into various warring fractions? War for control of the Matrix. And humanity is caught in the middle of it?