At the core of the production is Voltaire's realist attack against the optimist Gottfried Leibniz, whose philosophy is paraphrased in the second song of the first act,
Once one dismisses the rest of all possible worlds /
One finds that this is the best of all possible worlds.
Through ironic misfortunes of grossly optimistic characters, the resolution of the show is the eventual discovery of realism as optimism is made to appear largely ridiculous. In the end, Candide decides that since he can know nothing other than what is, he should just work the day away and find happiness in his daily toil.
The production effectively reveals the folly of the statement, "Once one dismisses all other possible worlds, one find that this is the best of all possible worlds." But it does so by attacking the second part of the line--that this is the best of all possible worlds. The production does not call into question the assumption that all other possible worlds should be dismissed. Similarly, as the show made fun of the church, it made fun of a church full of corruption that blindly proclaimed that all things as they are are for the best. It didn't deal with the fact that the church at its best does not concede the point that all other possible worlds can be dismissed; nor does it proclaim that the world as we know it is the best of possible worlds.
This is perhaps the failure of traditional liberal theology which rises out of the optimistic enlightenment. We need a way of acknowledging that this is not the best of possible worlds while also realizing that because of grace in Christ we are empowered to, in union with God, work towards a world which more perfectly reflects the Reign of God (the best of all possible worlds--taking into account the rest of all possible worlds).