I think a power-sharing model is the only way forward. Of course, with the examples you mentioned, sometimes it devolves into government paralysis such as in Cypress, or civil war such as in Lebanon, and so forth. The big problem here has been lack of power sharing, lack of trust between different communities, and whoever is holding the central government doesn't trust the others and seeks to hoard and consolidate all the power in their hands.
If we could reassure, in both administrative and financial terms, extensive degrees of decentralization and power sharing, I think it would go a long way to preventing future conflict. I think the Dayton accords in Bosnia have been an unsung success story. It's not perfect. A lot of problems remain. I've been to Bosnia a few times since then, and the story I hear is that no one is quite satisfied but they're all satisfied enough not to shoot each other.