I doubt there is a best possible world; and if there is, I’m pretty sure we’re not in it. All the same, I don’t think it’s quite fair to say “A claim that we’re living in the best of all possible worlds can only be read as a defense of the status quo.” (Traditionally it’s a defense of God, which is a somewhat different matter.) Conceivably, the best of all possible worlds might be one in which dramatic progress steadily occurs, led by rabblerousers and malcontents — so that resistance to the status quo would be part of what makes this the best possible world.