Or maybe he's crazy like a fox and was courting Russia and China to counter the EU as gambler brinkmanship, but if that was true, there would be a deal by now, not a referendum that will, most likely, remove Greece from the EU.
As a Greek-American I'm always shocked at how extremist the people are there when I visit. They're not like Germans who take something of a middle of the road approach, at least by Euro standards. They're an entirely different beast and I think other EU members are only starting to notice. The EU taking on Greece is like the US making Cuba the 51st state. The culture and governmental divides are huge. It was a bad idea from the start.
I suspect Greece is lost to the EU and somewhat to the West for quite some time. Greeks are prideful people and "OXI" is ingrained into their culture, good or bad.