Here are some "_______ to a Virgin Earth" posts I made for fun.
I like the enthousiasm, but ultimately, these
are "just" maps of the relevant regions, placed on an empty planet... with nothing else shown. The point of an ISOT is to show what
happens next. How do these countries thrive, fail, change, develop etc. in this new and empty world? If you don't try to show that, it's a bit of a shallow scenario, isn't it? You did it right with your "vanished Russia" scenario-- more like that, please!
To give an example of what I mean, this is a take on your "Central Powers in 1914" ISOT:
As you can see, I imagine things changing. This is my take on the world, 50 years later. Things have moved on in that time. I imagine that with no external powers around, the Catholic southern states of germany will be less inclined to be bossed around by Prussia. I have them gravitating into a Habsburg-led union instead. Meanwhile, the Habsburgs lose control of their more eastern territories. They might be able to hold them by force, but moving into a lot of empty territory to the west (just there for the taking) is more attractive. As such, Italians from Trentino start building their own kingdom, Croats and Serbs spin off into independence, and the Hungarians go off on their own. The Romanian attempt at creating a country for themselves is rather hampered due to being in between Hungary and Bulgaria, but though small, they are at least free.
The Ottomans lose control over their Arabic hinterland in the confusion of the "event", but soon see a chance to expand their Turkic empire in various directions. The Arabs set up two competing caliphates (one shia, one sunni) and the Armenians and Kurds found independent kingdoms on the eastern fringes of the Ottoman domains.
In Africa, the Ottomans dominate the northern shores and some intrepid Arabs are settling the Horn, but the greater share is claimed by the Prussian Empire. Their colonies shrunk back to coastal settlements soon after the "event", but with Berlin commanding the most powerful fleet remaining on earth, contact was soon re-established. The acttal colonies slowly began expanding again, and Prussia claims vast swaths of Africa.
In America, both Prussia and the South German Empire have quickly set up colonies at strategic locations, mostly with an eye to the future-- none of these settlements is really thriving yet.
Over in the far east, Germany's colony in New Guinea failed spectacularly before any German ships reached it. It took even longer to re-establish contact with the German holdings in China. As it turns out, these had been doing very well on their own. The entire economic exclusive zone got ISOTed, so there were a lot of Chinese and relatively few Germans-- but the Germans had the ilitary-grade weapons. What has emerged is a bit like a Raj, with a German aristocracy presiding over a Chinese country. Some intermarriage was required almost at once to avoid revolts, and once Prussian ships re-established contact a decade later, the former colony was no longer interested in re-joining Imperial Prussia.
(I'd really like to see how
you picture this scenario, or any of the others you posted, changing over the years and decades,
@TheDetailer.)