Vote #1 Emre Sermutlu’s answer. Because I’m just some random Greek. Emre Sermutlu’s answer to Why hasn’t Turkey adopted federalism if it is big enough and divided into seven regions?
Turkish Quorans may know me as an interested neighbour (Greek). Being Greek, the para about Turks being forced on the defensive in Emre’s answer is one that of course I’m going to disagree with. The Young Turks were plenty nationalistic on their own. The real point was that both the Young Turks and the Greeks and Armenians were not prepared to live together in a multiethnic Ottoman Empire—even if it was no longer one where the Muslims were privileged.
But with the overall tenor of Emre’s answer, of course I agree:
Different groups must like each other enough to be the part of the same structure, yet they must feel [my edit] different enough to warrant their own sub-structure.
And of course, there’s a third component. The ruling class of the country must not feel threatened by the difference of groups in the structure.
The guys in Trabzon, who Emre says will beat you up if you advocate for their autonomy, would also be sympathetic to the stunting of Turkish dialectology until fairly recently in Turkey: “There are no dialects of Turkish! There is only Turkish!”
And before anyone says anything, Greece has long done exactly the same thing.