Italy
In Italy the Church should have survived to the apocalypse,for example the Pope could have buyed a great bunker under the Vatican City,so after the great war the clergy went out,and formed a confederation of villages ruled by priest and mainly with farming-text and technologies preservating attitudes,in central italy of course,in the northern part there could be a situation similar to the American great Cities hit by the bombs,and so gang's raids,little comunities of refugees,and maybe a major faction composed by ex policemen and soldiers,who tries to rebuilt Italy,soome kind of Italian Enclave,and also a situation like fallout new vegas,with a Major of the cities(like mister house)brought by the Italian Army,who has to deal with Gangsmafia and also has to rule a ruined city...and to deal with the church!,there is also the Padanians moovement who will try to create an indipendent state,and Venetian Pirates or Venetian navy of Italy,in war,in South Italy there shoul be Mafia,and so families that fight with each other(like new reno)and a population essentially enslaved(what a pity T.T)but also a rebel faction,the Vespri,who will win?
France
France will have obviously his own Enclave,or France Army,but it'll be less powerfull cause the church would give less help,there would also be the Legion(not Cesar's one,i'm talking of the army)who will act like some kind of rangers-mercenaries-brotherhood,killing criminals and bounty,enstabilishing pact of protection with the villagers in eschange of resources and other stuff like that,Paris would be like a fusion between New Vegas and Washington,and so a city essentially empty,ruled at the center by the Enclave and the Legion,with Minor gangs and a lot of people seeking for fortune..or death!,i imagine france very desolated to tel the truth...but maybe with agriculture they should not give up!
Switzerland
in switzerland there are bunkers for the 99%of the population,that means that they could re emerge without deaths,and reboult their nation,with they ethical of "work,work work!" and theyr religious fervour(sometimes Calvinist,some kind Catholic,and so allied with the church)and they will be neutral....or mercenaries..who knows...
Germany
Hitler was....ahahah i'm joking,there won't be Nazi ghouls or an Empire ruled by post apocalyptic police,there will just be the government tryng to keep order,gangs....nothing of intresting....apart from dukies,yes,probably the old aristocrats would come back after the war and re enstabilish they rule on the various region,like a modern holy roman empire,with the govermnent sometime allied,sometime not,and Communist Riots in favour of the population.
In Eastern europe there should be just little comunities of surviving people traveling to seek food and resources,while Albany that still have a lot of bunkers and weapons,should became a great empire,enslaving people..or just helping theme,depends on the situation...and Greece will still be populated by comunities of peopletryng to live in peace,...but maybe some gangs will try tu emulate sparta..creating a violent faction"Spartans",in Spain there could be a great civil war,between communists,the governments,and so the king,that will try to put aristocrats to rule the cities....England,well there is jet a discussion so i'll not copy....Norwich coul be like the commonwealth...full of scientist..and they also have some bunkers..so i think that they'll be like the BOS..and that they will expand.....