Oh, absolutely. I don't mean to suggest that that sort of local experimentation* isn't valuable: as you say, removing the ability for variation reduces policy to guesswork. It seems to me that that's more possible in a situation with a clearer idea of success (i.e. a stronger regional economy) than is possible with states that have competing priorities.

* In re-reading, I think my bias is to call that local variation experimentation rather than competition. I'm a technocrat at heart.