Dave, you assert that the universe could not just exist, saying it is obvious. The trouble with saying that it can't come from nothing is that there is no suggestion it did come from nothing.
Coming from nothing will imply a flow of time in the nothing; no time there means no cause and effect, so you have a logic problem here. Time is a feature of the material universe - there does not need to be a before! No before means no need for a creation.
So explain the necessary role of god when no causation was necessary.
Alexander Vilenkin, Professor of Physics and Director of the Institute of Cosmology at Tufts University in "96" wrote “according to quantum mechanics”, tiny particles of matter are popping in and out of existence “from nothing”, and “if a particle can pop into existence from nothing then why not a whole universe?” --Discover Feb. 1996
http://www.youtube.com/watch?v=_XYGo3wjdoM
I'm not exactly sure what else you're trying to say so I don't know what you mean when you want me to explain the necessary role of god when no causation was necessary. Please elaborate a little more.
--Dave