I recently finished Robert Adams' old article "The Virtue of Faith" (chapter 1 of the book The Virtue of Faith), and I found a really interesting point. Uncertainty and faith are necessary for a certain sort of special good in a relationship. I think it's worth quoting Adams on this:
Well, suppose we always saw what people were like, and particularly what they would do in any situation in which we might have to do with them. How would we relate to people if we had such knowledge of them? I think we would manipulate them. I do not mean that we would necessarily treat people in a selfish or immoral way, but I think we could not help having an attitude of control toward them. And I think the necessity we would be under, to have such an attitude, would be conceptual and not merely causal. If I pursued my own ends in relation to you, knowing exactly how you would respond to every move, I would be manipulating you as much as I manipulate a typewriter or any other inanimate object. And if at some point I refrained from pursuing my own ends, in order to defer to some desire of yours, I would be manipulating you in the service of your end that I had made my own. By the very nature of the case I could not escape from this manipulative role except insofar as I could forget or ignore what I knew about the responses you would make...
Our actual uncertainty about what other people will do makes it possible to depend on another person in a way that is much more personal. It enables the other person to be more truly other. To the extent that I realize that I do not know how he will respond to my action, I cannot regard him as an extension of my faculty of action, as I regard my typewriter.
Even in the actual world, with all its uncertainties, trust is often manipulative. If I trust the bus driver, it is to take me exactly where I expect her to take me, with no unpleasant surprises en route... In cases like these the trust, and indeed the whole personal relation, is not an end in itself, but a means to the individual ends of the parties involved.
There are other relationships, however, in which we open our lives to be influenced and partly shaped by the other person in ways that we cannot predict very precisely except that we have some confidence that they will be good. And even in that confidence we may be allowing the other person some part in defining our good. Uncertainty allows these relationships to be largely nonmanipulative, and I believe the relationships that seem most intensely personal are of this type. It is not easy to say exactly what is so good about the dependence--usually a mutual but often an unequal dependence--in these relationships. But I am sure that it is logically and not just causally necessary for whatever it is that we value so highly in the best personal relationships. (20-22)
I find these points very insightful and penetrating, although there are a few parts that are harder to follow than others. I'm surprised I've never come across this literature (but I am still young!) We can separate two claims from this passage:
1) Uncertainty and faith are necessary for a certain type of good personal relationship
2) Uncertainty and faith are necessary for the best personal relationships.
I find (1) unproblematic, but (2) is problematic. The members of the Trinity, I think, know with perfect certainty what the others members will do, but I think their relationships exemplify the best type of personal relationship. We could keep (2) and reject either the claim that
a) the members of the Trinity know with perfect certainty what the other members will do, or
b) the relationships amongst the members of the Trinity exemplify the best type of relationship.
I'd rather reject (2).
Regarding God's relationship w/us, God would have perfect certainty of what we would do; hence, I would conclude that our relationship with God does not exemplify the best type of relationship (since the relationship amongst the members of the Trinity does). However, one part of the good-making feature of uncertainty, our uncertainty in and faith in God, can still be exemplified in the God-man relationship. It just wouldn't go vice versa. God needs no faith in us, nor does lack any certainty about what we will or would do.
On the other hand, I can see a little more clearly what some open theists find dislikable about the other views. If God knows with certainty exactly what we would do in every possible situation, some aspect of a personal relationship (which is enjoyed among humans) seems to get lost in the way Adams describes. I don't know the open theism literature too well (didn't Hasker or some other open theist describe the Molinist God as some super-puppet-master or something?), but I'm sure this objection's been knocked around a bunch already.