This article highlights some of the dangers associated with decentralization. In this analysis, "decentralization" is taken to be the "pure" decentralization of fiscal federalism theory, that is, a system in which pure local governments raise pure local taxes and undertake pure local expenditures without the benefit of central government transfers. This is not a very realistic model, but it is the one used in the pro-decentralization theory, and it is useful for analytical purposes.
This article basically gives you a base you can use to understand the problems with federalism in general. Somalia is a federal state and will face problems it never had to face as a centralized republic.
http://documents.worldbank.org/curated/en/218141468739288067/pdf/multi-page.pdf