Christian compatibilist free will?

Something interesting came up in the comments on my post about the free will defense against the problem of evil, and I wish to recap it.

First, commenter James brought up the argument that God's omniscience contradicts free will.  Commenter Slightlymetaphysical brushed off the argument.  I would brush it off too.  Pshhh, why should omniscience contradict free will?  Just because you know what someone chose doesn't mean that they didn't choose it.

Of course, the reason I would brush it off is because I'm very used to compatibilist free will.  That is, I believe free will is compatible with determinism.  An act of free will is just something that is arises directly from a set of conscious cognitive processes.  Even if those cognitive processes are deterministic, that doesn't mean our decisions weren't caused by them.

But there are also incompatibilist conceptions of free will.  For example, commenter Larry offered the following definition (without necessarily endorsing it):

1. Assume there is some state of the world at time t.
2. Agent A makes decision D at time t+1.
3. We "roll back" the world precisely to its state at time t
4. Agent A has "free will" if and only if she could make a different decision, D', at time t+1.

Clearly, this kind of "free will" is incompatible with determinism, because in a deterministic world, there is only one possible outcome, given initial conditions.

As a result of the comment discussion, I realized that Christians are implicitly taking a compatibilist view of free will.  As long as they accept the following premises, they must accept the conclusion:

Premise 1: Free will exists.
Premise 2: An omniscient being exists.
Premise 3: The existence of omniscience implies determinism.
Conclusion: Free will is compatible with determinism.

This is very interesting, because it is not in accordance with other Christian views on free will.  And in particular, it's not in accordance with the free will defense against the problem of evil.

The Christian* view on free will is that it is the ability to turn against God.  Eve had the ability to eat that apple (or pomegranate or what have you), and the ability to choose not to.  For reasons infathomable, this kind of free will is so desirable to God that it is worth the evil that proceeds from it.  On the other hand, if we believe in compatibilist free will, then God can have his cake and eat it too.  That is, people can have the ability to choose evil, even when it is predetermined that they will not exercise this ability.

*More accurately, a Christian view, which is not necessarily universal among Christians.

The problem of evil is the question, "Why does God allow evil?"  The free will defense is, "Evil is a necessary consequence of free will."  My proposed counter is, "But free will is compatible with a world where no one chooses evil."

Of course, this is one of those purely philosophical arguments, and we all know how unpersuasive those are.  Here are a couple responses:

• Omniscience does not imply determinism. An omniscient being could simply be aware of all possibilities and their outcomes, without knowing which possibilities will come to pass.  One could counter that this kind of omniscience is hardly a proper omniscience at all.  But I for one would still be very impressed by such a being, whether it's proper omniscience or not.
• It is not free will itself that God finds so desirable.  Rather, God desires that people have the ability to go against him, and that they actually exercise this ability.  God's desire does apply to heaven, where he is basically okay with the fact that everyone is choosing good.  God sure has some strange desires, but the truth can be strange.