God is by definition a conscious being. But consciousness is itself an incredibly complex phenomenon, so God must be an incredibly complex being. God, if he exists, would be an extremely complex being that is also fundamentally complex, and this implies that the existence of God is extremely improbable. In evaluating any argument, it is always useful to formally write out the argument, explicitly listing the premises and making sure that the logical structure is valid. Extremely complex phenomena that cannot even in principle be explained as arising from simpler, more fundamental principles are extremely improbable.
Conscious beings are necessarily extremely complex.
The existence of this type of phenomena would mean that science could not proceed. They could claim that human consciousness may be complex, but the supernatural, spiritual consciousness of God is not. This type of claim, however, cannot be correct. To see that consciousness itself is complex, consider that consciousness requires the ability to store and access information that is linked together in many intricate ways as well as the ability to process that information and to reason. The web of intricately interconnected data that consciousness requires is extremely complex.