Your concern about tying theology too closely to a particular metaphysics is
certainly justified. However, I think that it is inevitable that we attempt to
frame our understanding of God's interaction with mankind in a broader context
of understanding; that's how we are designed.
Also, there are some instances in which a particular metaphysics, far from being
neutral, is actually inimical to the Christian faith. Process philosophy, for
example, has greatly influenced theology in this century, and offers a model of
God that is the opposite of the model assumed by Aquinas, Calvin and Luther.
Their God was the God of timelessness, immutability and foreknowledge; process
theism denies these, or at least redefines them until they mean something
entirely different. The Process God is Itself evolving with the universe in the
flux of time, and not superintending all things from without, as in the
classical model.
In short, I would prefer classical theism, more compatible with Aristotle, than
process theism, based on the metaphysics of Whitehead. Neither of them have
exhausted the truth, and, as always, Scripture has veto power. Nevertheless, one
seems closer to the God of Scripture than the other. Therefore, some measure of
metaphysical commitment is both inevitable and necessary.
Jeff