We had this discussion a long time ago here, as I recall. Tracy, whose posts you may have read, gave some very good points from some of the more respected scholars of our day -- if I remember right -- and with links.
At bottom of it, open theism posits that God does not know the entire future, that the future is changeable and that God has limited knowledge of it since we have not yet made choices that affect the future, etc.
One website (opentheism dot info) says this: "the only wise God has chosen to exercise general rather than meticulous providence, allowing space for us to operate and for God to be creative and resourceful in working with us. It was solely God's decision not to control every detail that happens in our lives. Moreover, God has flexible strategies. Though the divine nature does not change, God reacts to contingencies, even adjusting his plans, if necessary, to take into account the decisions of his free creatures. God is endlessly resourceful and wise in working towards the fulfillment of his ultimate goals."
Yet, the very hairs of our head are numbered, Jesus says (a claim open theists take as merely hyperbole, idiom). It defies God's sovereignty as revealed in the Scripture to say that God watches us, as the song says, "from a distance", that God is really not in control so much, and that much of what happens in His creation is out of His hands. The Bible, under open theism, reads like a Nancy Pelosi strategy .... God can't know what's in the future until the future happens. (Which means God can't know the future period.)
I can't and won't try to exhaust all the arguments on the issue. For me, if one argument is good enough to falsify a premise, no others are needed. And, I'd submit this link to you as a starting point.
http://www.desiringgod.org/resource-lib ... w-covenant