Well, Batman and Superman being centre made sense because it was Grant's deconstruction of comic book form and DCU in the same place, and those are the two most famous icons. Doesn't excuse the fact that more could've been done with it (heightening the mythic, while emphasizing the human), and especially that Diana didn't get any kick-ass moments here.
However, I think that Mr. Morrison would've put in the Vedics if he had read any Wonder Woman. The man is a nut for Eastern philosophy. He would've been all over that shit.
See, in my mind, the war would've started probably much the same - removal of the Big Three, Anti-Life, etc. But it should've been a smorgsabord of Myth and Humanity vs. the concept of Absolute End, because when One Mind controls all it is the end of Fictional Reality and the creation of One Reality, which can be analogous to the Reader/Audience. Because one of the fascination of Fiction is that we are looking into OTHER realities, that are cogent and coherent and fully realized, outside the framework of our own reality, which is informed by a variety of forces but not anyone else's reality, just the reality that we percieve. It works into Morrison's deconstruction fascination, yet also highlights the power of Storytelling. Also, emphasizing Myth and Humanity is something that Morrison has done very well, especially in JLA. I know that One Million wasn't everyone's cup of tea but I loved the idea that the Myth, also known as the Legacy, of a particular Hero was what kept going on in the future - and you can highlight that with the reality. Imagine a fight of Myth - not only the mythological characters and pantheons such as the Marvels and the Greeks, but the Myth of the prime Three, and what they represent in the comic book context.
...okay, I just read over my stuff and I think it's largely incoherent. Bleh.
Also, Batman never shoots somebody, and if he ever dies he dies on the streets, where he belongs in every way possible.