How many nations are they planning to add in total?
According to secret info deep hidden in a secret fortress of WWIV... they will add nations like Catalonia, Flemish, Wallonia, Faroe Islands, Bretons, Corsica, Savoy, Britanny, Occitans,... and they will be added in a Confederation of Imaginary Independent Nations in Orion's Arm (CIINOA)
Right now, as I understand... they will add the faction which wins this poll. After that I don't know but as devs stated several times.. their intention is to make the community part of game development with polls, feedbacks and so on. So, I have no idea but it's clear that this depends basically of the community's interest (1), the funds of the project (2) and the relative importance between the addition of factions and other gameplay mechanics/features (3)1
Imagine if the game only focus on adding nations, that means adding the same units (light, guards, carpenters) changing the color/uniform instead of making deep some sort of elements like the ability of carpenter to repair, a new type of unit to create new structures for the battlefield, unit focus on the use & management of the artillery, deeper & complex mechanics of the soldiers, improve of the server's efficiency to increase server's capacity to make battle huge, etcétera.