I hate to bust your little pink balloon, but this kind of story was never meant to be or never fit to be squeezed within the constraints of this genre. Madara didn't kill anyone for no apparent reason. When the only people on the field are military and the rest of the world still exists and vastly outnumbers this alliance. OMG no way? But it's quite correct. The hidden villages only make a small portion of the countries and the alliances are made of the strongest villages. There are countless others and many countries do not even have military Hidden Villages.
That much was made clear within the first part of the manga. Now what stopped Madara from killing all of them? Nothing at all. His Eternal Tsukuyomi would have been just as affective on the overwhelming majority that has nothing to do with this war. Loo at Obito now; the guy has Creation of All Things at his Disposal - Izanagi in higher form - and can accomplish literally anything with it. But he mostly stuck negating techniques. Why doesn't he create a giant water dome around the alliance and drown them?
This manga is beyond stupid and I am only sticking around to see it end. So this thread of yours doesn't make sense to me, given that Kishimoto's choice of genre is limiting, suffocating, constricting, and largely boring in its approach as nothing can be exploited to its full extent to take a bit of realistic liberty. Madara and everyone else, naturally, fall victim to this redundancy. Take everything into consideration if you make such threads. Piece of advise.