I don't really understand its relationship with the Empire, but it would open up yet another front for the Empire if it turned hostile. Say a Russian or Chinese-backed coup installs an anti-Roman nationalist government espousing the idea of Greater Ethiopia or Pan-Africanism. Ethiopia would then have several directions to expand. First, it could take Somalia and Madagascar. Second, it could advance into South Africa and the countries between southern Ethiopia and South Africa. Then it could attack the Congo. Finally, it could attack Arabia and then invade the Empire. I'm not really sure what to do besides this.