Unfortunately, anyone thinking of delaying their SHA-2 migration in hopes of moving directly to SHA-3 will be greatly disappointed. Widespread adoption of SHA-3 is probably many years away, whereas SHA-2 is required now. If you moved to SHA-3 now, most, if not all, of your cryptographic-relying applications and devices would probably error out (saying they cannot recognize the digital certificate).
So, if you’re not already migrated to SHA-2, get going now. And when SHA-2 starts to get weakened, we can all move to SHA-3.