Indeed. Red Tide, and Vietnam(and probably Condemned Heroes too) are flat out mission packs, they could have been made for Faces of War for all we know. I dont really consider MoW a sequel after FoW, hell, the russian versions dont do that either.
On the other hand Assault Squad delivers improvements to gameplay, and maybe even graphics to warrant a FoW 2.0 title in my eyes. Yes, its a bit on the Unreal Tournament 2004 side, after Unreal 2, but what the hell, at least it plays differently. ^.^