Maybe dumb, but did you think of giving the Gondor similar ability Rohan has - give them three Captains of Gondor? Notably i mean the Hurin The Keeper of The Keys, Forlong of Lossarnach and Hirluin of the Green Hills. They do not appear in the movie, but they were mentioned in the original lore, ant if i am correct, they played not the least role in battles of Pelargir and Pelennor.