I see no engine available and suitable for the next FH yet. You need some basics first. Like the ability to run infantry, vehicles and aircraft on maps big enough for all of them to work properly. Including proper collisions for all of them. If you take an average FPS shooter these days, you'll clearly see that most mapsizes are too small for vehicle combat. There are shooters dealing either vehicle combat or infantry combat. But not both. Except BF3.
The Unreal engine and the Cry engine are craptastic for vehicle combat, as maps are too small. The Arma engine is 15 years and outdated. The C.o.D. IW 4.0 engine is not suitable for vehicles either. The S.T.A.L.K.E.R. X-ray engine gets outdated and has never been approved for vehicles.
But if you think you've found a suitable engine, that also has been sold that numerous, that it is available in every household these days, then let us know.