I knew that this would be a hard post
I am very interested with the variety of responses that this topic has drawn out of us thus far. The accident of birth, the reality of evil, the serendipity of love, and the importance of agency have all been covered. What else could I add?
The problem of foreordaination seems to hinge on the problem of a fixed future. If the end is fixed, as we believe it is, does that make the path fixed also? There is a powerful tendancy to believe this. I am not sure that it is helpful, but it may be inevitable.
The consequence of a fixed future is that individuals are just the means to gain the end. Even if anyone could be a Joseph Smith or a Judas, someone has to be both. Or do they?
Are the questions of foreordaination just another conceit of human pride? Do we know that it had to be the way it was? By this, I am not suggesting that there are versions of the plan that do not feature our Fall, that much seems certain; without a Fall, how do we get an Atonement? Rather, why is it that, just because the Atonement played out a particular way in our world, we assume that the path taken to get there was the only possible path?
I am not saying that it isn't; I am saying that we, ultimately, don't seem to know. If all that we agree on is that the end is fixed (which we do, in the church at least), then anything further that we might come up with is just speculation (barring revelation, of course).
Part of the reason why we assume that this is the only path is that we have assumptions about God. In particular, while we believe that there is a necessary amount of suffering necessary for the Plan to work, we believe that a loving, omnisicent, and omnipotent God would only allow that amount and not a drop more. This operates in a nice parallel with the idea of the fixed ending (God allows suffering up to level A, after which the cup of the sinner is full and they are wiped off the face of the earth). Ultimately, it doesn't matter how you get there, just that you do.
Unfortunately, the only amount of suffering that seems to be fixed is Christ's and that was set at infinite. There does not appear to be an end to suffering in this life; arguably, it is one of God's greatest tools for getting us to turn to Him. Not that he causes it, but he clearly doesn't always prevent it when he theoretically could.
Foreordaination is disturbing because it causes us to examine what role God plays in our life and what role we play. Much like the recent hurricanes, it reminds us how little our life is of our own making. Although how we choose to deal with the life we have is entirely up to us, the random acts of kindness and destruction that we encounter enforce a situation where all our plans are tentative. While the Plan has a fixed future, we rarely seem to.
Perhaps this is for the best. Uncertainty, like suffering, can bring us to God and that seems to be the end for which our lives should be destined anyway.