I'm curious if this exodus will actually decrease mining centralization or not. There's a popular belief that somewhere between 70% and 80% of mining power concentrated in hands of just a few pool owners, and that Bitmain can leverage their monopolistic position influence the miners, so even if Chinese miners will scatter across the globe, they still might depend on Bitmain and pools.
there are two separate issues. one is geographic concentration. an exodus of hash power away from china is a positive development. people have been worried for years about the chinese government's ability to drastically affect the hash rate with government action. this alleviates that concern. the GFW has also been a concern with regard to block propagation delays with bigger blocks (since the majority of hash rate is within the GFW), so there's another potential benefit.
the other issue is majority hash rate concentration among only a few ASIC manufacturers and pool operators. bitmain has already been setting up outside of china for years. they back multiple pools in different localities. they have mining facilities all over the world. they have mining facilities in canada and are apparently buying more. i've seen reports they are looking into swiss facilities as well.
i'm hoping that this problems is mitigated by new ASIC manufacturers entering the marketplace. GMO and dragonmint come to mind, but i'll believe it when i see production units and market share being taken from bitmain!