I'm confused. Did it not end in 3 when he died after defeating Smith?
The Matrix is, under all the fX, about WTF is reality anyway.
For post graduate work on WTF is reality anyway there are no better texts than the works of Philip K ***.
I mean, sure, but it's a story first and foremost. A story that uses broad strokes tropes, and was quite satisfactorily finished from my PoV. What else is there to add, except cooler portrayals of the same ideas?
Did you notice how in the trailer there is basically a barrage of callbacks and references to the first Matrix movie? It almost feels more like a reboot of the series than a continuation.
I'll probably see it, but I don't have any expectations or hyped up hopes.