I say, take the unreal engine, port a gun and a player model from fh2, try to implement the battlfield game mechanics and push out a first simple map that can be played. Then continiue to improve that in a "open" fashion with a server that always runs the current developer version and that allows quick feedback from the testsers.
This might attrackt the attention of more developers early and breathe some live into this community.
Don't do it like Traction Wars were they work secretly for a decade on stuff and maybe in the end the team is desolved before they publish anything.