i also think they would rule longer, but they definitely would have had to change some things because the reason it failed is because isolationism was enforced during that time, and also in that time their were new developments, which of coarse china didnt hear of because they had the isolationism enforced so when they were attacked, they werent as advanced!at least thats what i think, or it was just that the japanese forces were much stronger wen they attacked them in 1274 and 1281.that could be the reason too...