I read Rev.16 verses 14,16 again and yet more now I can hardly understand why this short high symbolic text should be read as a "final solution" for the whole world of unbelievers and a "of most importance" text in the bible. Also Armageddon seems to be not " a war in heaven" but "more earth-orientied " because of the " kings of the nations " mentioned, which could be a phrase chosen by John to mean simple the Roman empire which then was the whole world, but he avoided it to call Rome.
This WAR of wrath - part of the 7 bowls of wrath -- was then I think simple a part of the 6th bowls of Gods wrath - the wrath against Babylon/Rome and not about the end of the world, killing of all unbelievers, as the river Euphrat are mentioned in the same verse as armageddon.
Read the 7th bowl and it again speaks about BAbylon. So everything seems to point to an earthly wrath against the Roman empire in which all kings of all nations take symbolically part and to which they congregate themselves at a symbolic place of Armageddon, this is language of hope, that was used in the Johanite community liturgy. The terminology of war was present but in highly symbolic use.
So I think John or the first christians did not mean Armagedon a war against all nonbelievers at the end of time but Armageddon to be a war of babylon the great which riding and influencing all kings against holy church and God's wrath against babylon afterwards.
The other more heavenly "war in heaven" - according to your definition - in which a dragon and michael appears is another subject yet more interesting for my later post.