just to be a bit of a completionist, but isn't a form of it used in the generation of your "domain" from settlement centres? You don't have anything to increase what the settlements generate, but it's "there". I take advantage of my expanding domain to take outposts whenever possible in game from the ai without declaring war.

 So why was it removed? I didn't play FE, took some time away between Elemental :war of magic and FE:LH to let stardock try and get things together but sounds like influence might have been a fun aspect, if its anything like Gal Civ's. Generally sad to see things removed from a game to make it easier. While LH is a fun game and I've played it 300 hours worth already I find it somewhat limited and the AI mid to late game somewhat dull and boring as frequently it seems to be a case where every position basically dog piles on you for some coins the main AI offers them to commit suicide, and its one fairly long and dull slog killing them all off for their stupidity.