Matt Yglesias makes the point in splendid fashion:
We should let a thousand flowers bloom and then kill 20-30 percent of them if they turn out to look ugly.
Logically, mind you, this is how we might approach other policy questions. In Britain, that might mean welcoming regional variation in the NHS (Oh noes! Not the Postcode Lottery!) and treating that as a feature, not a bug. Then we could learn from each other and see what works best in any given set of circumstances. Centrifugal* forces are your friend, not the enemy.