It doesn't, of course. Open Theism continues to seem theologically inadequate. Even while I grasp the good-hearted spiritual yearning that underlies it, its view of God is too narrow, to small, and too temporally bounded. God is, for the Open Theists, aware of past and present, but can't predict what will come to pass. In this, the God of Open Theism isn't so much a Deist Clockmaker as a parent who sends a woefully unprepared child down a double diamond ski-slope.
"Honey, bend your knees. Look where you're going. No. NO! LEFT! GO LEFT! LEEEEEFFFT! LOOOK OUT FOR THAT...OOOOH! AND THAT... Oh. My. That'll make failblog for sure."
This is not the I Am That I Am, nor is it the God who lays it down for Job, nor is it the God Jesus called Father. It's a minor and slightly bumbling demigod in the Canaanite pantheon.
Where there is theological weight to Sanders' arguments is in his exploration of the meaningfulness of repentance in the classical model of God's sovereignty. If the universe is a single narrative stream, one linear sequence of events from the moment of creation to the moment things end, then there is no way to reconcile an omnipotent and omniscient Creator with the concept of repentance.
If everything is as God wills it, then we sin because God intended us to sin. As Sanders puts it:
According to specific sovereignty nothing happens that God does not want to happen. Every state of affairs, including my personal holiness, is precisely what God desires. (p. 251)So if we sin, it is not that our volition is out of keeping with God's intent. It can't be. Nothing is out of keeping with God's intent. God wills you to do that fifth shot. God wills you to shake that thang. If God didn't, then you couldn't do it. Or so the argument goes.
That is equally true of repentance, which is as predetermined as just keepin' on sinnin.' Given that it's all God, the meaningfulness of human response to God's grace is, under that system of thought, kinda questionable. Resolving that tension has always been the challenge for thems of us who are Calvinish, and none of the deterministic responses laid out in the God Who Risks (pp. 252-254) are particularly strong conceptually. If there is no probability that we will do what is not God's will, then we can be hardly be faulted for our actions, or rewarded from turning away from evil.
That's not to say that what Sanders proposes is much better. A weakly contingent God is hardly either optimal or theologically robust.
But if human will is part of the process of a dynamic multiverse creation, then the manifold providence of God includes our will, our acting, our doing, and our agency. Our decisions matter, and govern the way in which we stand in relationship to our Creator in the time and space we have been graciously given. Sin...turning away from love of God and love of neighbor...becomes a choice with deep weight. It also becomes a choice, not just the turning of the cogs of destiny.
As does repentance. And without repentance, the Gospel has no meaning.