I'd say it's harder to refactor because you can only refactor to correct programs. Other, more lax languages are easier to refactor to a wrong new state.
But isn't that the goal? Namely to automatically (without human interference) refactor to a correct program?
...Or at least I hope that will be the case in the future. But like you, I believe it's much better positioned to do so compared to the dynamically-typed languages.