Naturally, we don't normally phrase it that way. A phrase I commonly use - with my tongue only slightly placed in my cheek - is, "If I were king of the world." Common variations on this are "If I were president" or "Congress really ought to" or "There oughta be a law."
It's not just that we want someone whose word is Law, or can institute change at will; we want to be that someone. Often, we don't want the responsibility or accountability that comes with being in charge. So, if we are really honest with ourselves, what we really want is to be puppet masters. We would directly control a figure head who would enact our wishes, and accept the responsibility for the consequences.
I suspect this view of an omnipotent God has its origins in childhood. Child development psychologists have suggested that infants perceive themselves as the "center of the universe", which is to say, as a type of god; their needs are met upon demand - and often before demand.
Another theory is that infants and young children perceive their parents (especially the mother) as gods, because the basic needs of life are provided by these large creatures. Parents also serve a God-like function as they correct and praise the child.
So the average child faces a couple of disappointments early in life: first, that the child is not god. At some point, the child will be expected to become increasingly self-sufficient. Secondly, the child learns that his/her parents are not god, either. The parent will inevitably fail in some way.
It seems to me the vision of God as an omnipotent being is also a product of childhood. We want to believe in a God that is as powerful as we thought we were as infants. Often, we want to believe in a God who acts as we would act, and defines "good" and "bad" the same way we do.
I agree with St. Benedict, who said that the most we can know about God is what we don't know. These labels we like to use for God - omnipotent, omnipresent, good, kind, and so on - are means of limiting God to human terms. God may be all these things, but not necessarily in a way we can fully comprehend.
So, when someone says they don't believe in God because "God wouldn't allow x to happen", I understand that they are saying they don't believe in a particular definition of God. It's almost like the classic straw-man argument: they get to define God, then shoot down that definition.
This definition of God is essentially how that person would act if they were God. I'm not sure I could believe in that god, either.I believe in a God whose nature can only be hinted at. I still might use those age-old labels, but I understand those labels to be (at best) faded sign-posts. I can make some educated guesses about God based on my understanding of creation; but those guesses will only be as sound as my rudimentary understanding.