Calvinism is the worst theodicy–except for all the others

Churchill's quip reminds me of Calvinism and its critics. Here's a fascinating extension of Peter van Inwagen's theodicy:

God has a criterion for salvation. And he has a policy of enforcing it that goes as follows: If a creature meets the criterion for salvation, then admit him to Heaven. Otherwise he will end up in Hell. In creating a chancy world with free creatures and orderly laws of nature, God risked creating people that would not meet that criterion. For all we know, that is his plan and this is the world he created. And for all we know, just as it is not determinate that there is a minimum number of horrors required to realize the divine plan, it is not determinate that there is a minimum cutoff for satisfying the criterion of salvation. For any person in the indeterminate range that God saves, he may just as well have saved a slightly worse person who is also in that range. But this is no moral flaw of God’s, because – given that the criterion of salvation is indeterminate – it is not possible to always satisfy the proportional justice principle. In practical sorites situations, moral agents must arbitrarily discriminate between points in the series. For all we know, God faces a practical sorites in his plan of salvation. So, for all we know, premise (6) of Sider’s argument is false. p408.

Sullivan, M. (2013) Peter Van Inwagen's Defense, in The Blackwell Companion to the Problem of Evil (eds J. P. McBrayer and D. Howard-Snyder), John Wiley & Sons, Ltd, Oxford, UK,ch27

How's that supposed to be an improvement over what freewill theists find objectionable in Calvinism? Basically, salvation and damnation are the result of getting lucky or unlucky.