Composition wise this
is much better than this
why?
well, try to cover the right half of the first image with you palm, it feels kinda like something is missing, the image has lost a vital component - the angel. Now if you cover the left half of the second picture it gives a sense of a complete piece by itself. In other words, the second piece lacks cohesion and the viewer cannot find any noticeable interaction between the cities, thus it is hard to convey a conflict.
A workaround could be a viewer character:
and more missiles from both sides. this makes a triangle pattern for the viewer to follow.
another way to make the piece more dynamic would be to arrange them into a diagonal:
or a mixture of both:
you could also change the perspective of the viewer to change the whole meaning of the piece.
(sorry for the bad English)