So - according to a recent leak, it looks like these are going to be the available factions in Battlefield V, or Battlefield 2018, or whatever it is going to be called.
Great Britain
United States
Free French Forces
Third Reich
Kingdom of Italy
USSR
Imperial Japan
I’m pretty sure it’s going to WWII since BF1 was a experimental thing for DICE as they wasn’t sure if it would sell as a WWII straight away, but due to the success of both BF1 and CoD: WWII they went ahead.
The development of Battlefield2018 was WEL under way before COD WWI was released. IIRC it takes something like 2-3 years to make these games. Which would mean that development would have started right around the time of the Battlefield 1 launch.
The ship had already sailed on the direction that they were going with.