For me the dividing line is how the
Messiah loves us as he exercises his reign? "O LORD our Sovereign, how
majestic is your name in all the earth (Psalm 8:1). On one view God is like
a paternalistic monarch who decides what is best for us, is never influenced by our input, and never changes his mind.
I have set out my experience of God on this website in REIGNING WITH THE MESSIAH. In that I argue that our Sovereign Lord actually longs for my input in his dealing with nations and individuals. That means God is willing to be influenced by my prayers, and invites me to share in his reign. He invites me to sit on the jury to consider how to exercise wrath (e.g. Abraham in Genesis 18:22-33). How could I love, talk to, and actually reign with a God who is totally impassive and immutable?
So in the current discussions of Open Theism the point at issue is whether God is a benign paternalistic Father who decides what is good for us, and we have no input in his choices, or whether he wants us to be involved in his reign among the nations?