I agree with you that neither system is superior to the another. I also agree with you that both systems can embody democracy.
There is no reason for all countries of the world to have a federal form of government. I
t is suitable for some countries, but not for others. Countries that have found it preferable fall into five main categories, with some overlap :(Ethiopia ticks the top 3 criteria for choosing federal system.
(1) Countries that are geographically large : Russia, Canada, USA, Brazil, Australia, India, Argentina — that’s 7 of the world’s 8 largest nations geographically; only China is not officially a federation, and, in my opinion, would be a lot better off if it were to become one. Russia’s status is questionable : its Constitution defines it as one, but in practice, that appears to be pretty much a legal fiction.
(2) Countries that have a large population — i.e. >80 million : India, USA, Brazil, Pakistan, Nigeria, Russia, Mexico, Ethiopia, Germany. That’s 9 of the 16 with over 80 million — a figure I chose because it’s about 1% of the world’s population. Countries that are not federations : China, Indonesia, Japan, Bangladesh, Philippines, Egypt, Vietnam. Indonesia was a federation in the 1950s but changed to a unitary system. Politicians in Japan have been discussing the idea of changing to a federal system. As I mentioned under the first point, Russia’s inclusion is something of a legal fiction.
(3) Countries that are ethnically diverse, with ethnic boundaries largely corresponding to geographical boundaries : Russia, India, Iraq, Nigeria, Ethiopia, Somalia, Sudan, South Sudan, Nepal, Belgium, Bosnia, Switzerland. Of these, only Russia’s status is problematic. Former federations like Czechoslovakia and Yugoslavia, which dissolved after the Cold War, were also in this category.
(4) Islands differentiated by distinct character : Federated States of Micronesia, St Kitts and Nevis, Comoros. The former Federation of the West Indies (1958–1962), which Britain tried to implement among its then-colonies in the Caribbean, was also in this category.
(5) Federated monarchies (allowing each federal unit to retain its own monarchy) : Malaysia, United Arab Emirates. In the latter case, the federation is, in practice, asymmetrical : Dubai and Abu Dhabi dominate the federation, with the remaining states having little say over federal affairs. The former German Empire (1871–1918) was in this category, too : most of its constituent states were monarchies which retained considerable local autonomy, but the federal government was, in practice, an extension of the government of just one state : Prussia.
https://www.quora.com/What-factors-dete ... ent-system