I think I see it now. Dice came to Ea. They have the numbers. They have to see the modern day time fatigue better than us. They had to make a choice. Far future or Far Past. Everyone is doing future, and Dice had done 8 years in a row in near future times, with the only respites being digital games or expansions. Everyone, all 3 Cods, Battlefront, TitanFall, ect are going distant, sci-fi,Far future, or a mix.
By going that far back they take a risk, but also single themselves out on the market, in comparison to competition and internal products. I assume they were able to show a great pitch, and also assure EA that by making it alternative reailty they would be able to keep certian key elements of Battlefield, like the massive amounts of things to unlock. A good showing at E3 and GDC+ a public beta should get the public opinion turned around. It will still be an uphill battle.
What I find most interesting about this is I can't imagine WW1 being a 1 off thing. Not in the sense that this might become a trilogy, but more so that the furthest possible point was chosen to go back too. As in this will start a chain of games exploring different Wars and time periods pushing back up to the modern day. WW1, WW2, Korean War,Vietnam War, Desert Storm, Iraq Freedom ect.