This is actually a very old question that sometimes is brought forward in this Forum. From the top of my head, having read these discussions, I remember that people usually come to the conclusion that Ethiopia could not "pull a Meiji" like Japan did (at least not without a serious foreign European "godfather", like Britain or France), owing to its lack of a literate population and basic socioeconomic infrastructures (resources, transportation, capital-worth institutions and know-how) that allowed Japan to modernize so quickly. Japan was, in essence, a feudal country, but it was administratively (with an urban bureaucracy, for example) and economically more developed than Ethiopia in the 19th Century.
Now, I might be mistaken, as I'm not so familiar with Ethiopia, and more with Japan, so I predict that a more enlightened fellow might post a better explanation or possibly contradict what I'm saying.
Playing the devil's advocate, let's say that for some reason Ethiopia receives a significant "boost" from a foreign power, like the Ottoman Empire or even Britain (let's say the British pop some colonies in eastern Africa to allow better transportation to India and Oceania). While it struggles with basic issues such as infrastructural development and modernization of its military, it can cut some edge over its lesser developed neighbors in the Horn of Africa (Somalia, Eritrea), and might go as far as the Omani domains in the Zanzibar coast. I doubt the Ethiopans will try to go north beyond Sudan (not that there is anything worthwhile besides northern Egypt in that part of the continent, and then this part will be off-limits due to the European - Western or Turkish - interests). A more expansionist Ethiopia might go further south all the way to the African Great Lakes, but something beyond this might alarm any power interested in Africa, like Portugal, Britain or even France (if they replicate OTL protectorate over Madagascar).
You must take in mind that, due to Ethiopia's geographic position, it is not exactly in an "isolated" situation whatever developments it experiences, especially regarding the evolution of the military or even acquisition of resources from European or Asian markets will inevitably "spill" to its neighboring regions, especially Somalia, and this might, in a much smaller degree, create a space for an overall westernization of the region (something like what happened in Thailand with the colonization of Vietnam and Burma).