Germany and Japan were both cohesive societies Iran Irac Syria are not They are artificial constructs of the Sykes-Picot agreement of WWI
What is happening is the reversion of these states to their religious and tribal origins which we should encourage. There will never a Caliphate as the different factions will never agree
My position would be to keep Sunni and Shia odds and encourage Kurds to continue building their society and influence