In biology organisms have tended to get more complex over time and animals with larger and more complex brains seem to be more intelligent. But are we correct to infer from this that if God exists that he is simply a much more complex being than we are? What does “complex” really mean when you talk about God? Presumably it does not mean God has a larger or more complex brain. For many who believe in God he is not a “thing” that can be described in comparison with “things” in our experience. He stands outside of the universe, outside matter, outside time, outside of “being” as such. This is how God can be said not to be an added complication to reality as we know it, because he stands outside reality as such. He crafted reality and is not subject to it.
It's like you have a classroom full of 20 children left to their own devices and chaos rules. I suggest we add one more, and you say that will only add to the chaos. But I say let the additional one be a teacher and not a child. In this case the addition of another does not add to the chaos but instead solves it. In a similar way, adding God to our understanding of the world does not add complication, but instead provides order and coherence.