FPM - the current concept is a bit busted IMO
Military - only one faction, only one maintainer
Malevolent Rising - egregious copyright infringement, huge size, doesn't work for some people
Constellus - still a long way from complete, but has potential
WW1 - I haven't really seen enough of this to comment.
I figure it would be easiest to do a compilation. Rather than making an all-new tech tree, use the power of open source to combine some of the high-quality factions already made, and then modify/add a few units to take advantage of new GAE features and for balance purposes. We could have a pretty darn good generic post-Tolkien high fantasy tech tree with very little (new) work. Gameboy's Elves, Madmanntis' Woodsmen (pending one or two units), Wciow's Dwarves and Undead, modified Tech and Magic -- that's plenty of factions right there, and all are damned high-quality. Okay, I confess to never having played with the elves, but they looked awesome IIRC.