I didn't come to AA with a set belief in this whole "god" concept, but I wanted to stop drinking and couldn't do it.
I think where a lot of people get hung up on this is that they "think" they know what God is - to themselves and/or other people...from what I have gone through and many of my AA friends, God took on a whole new meaning somewhere during the actions taken in the 12 steps.
I was willing to believe that miracles do happen, so I started moving my feet.
I think I was six or eight months sober and I had this 'revelation' that I was AGNOSTIC, I truly truly was. I thought I believed in a higher power - I thought it was something that I could probably define and describe and box up neatly to fit my life. What I went through, and what I came to believe is that I will never "know" what god is...but I do believe there is this power I tapped somewhere in the steps and it is very very real. My attempts to define God or higher power only serve to limit it for myself and others. Finding this thing that I refer to as god - was the key to my getting sober, and staying sober....but I wanted soo much more than that, and I have received in abundance (I actually feel pretty much mostly good and happy most days... and haven't even thought of taking a drink).
I think a lot of what stops people from actually tapping this power is the inability to set prejudice aside..ie - approach the steps as if you have no idea what god/higher power is or does, and be open to experience that which is available to everyone.
Staring death in the face - I didn't much care if someone asked "are you willing to believe that there is a power that is greater than yourself - great enough to remove your alcoholism through some simple actions?"