When I was an atheist, I thought of God as a God-of-the-gaps, and a philosopher's God - an explanatory hypothesis - and indeed a grossly over-explanatory hypothesis: a cop-out.
I got the idea tha Christians (and others) saw God as so totally powerful that he could do anything; therefore, anything you wanted explained at any time, you could just say 'God did it' - which was so generally applicable that it left you pretty much where you started-out.
I didn't understand the concept of revelation - that what is known about God is a product not just of reason, of philosophical argument - but mainly of God revealing himself to Men. But if I had grasped the importance of revelation, I would have dismissed it as purely subjective, because there are so many different claims about what God has revealed. I would have wondered why this all powerful God could not do a better job of communicating unambiguously and clearly with Men - or better still, why he had not built-in all the knowledge that Man needed, so communication by revelation was not required.
Also, although I knew that the Christian God was a God-of-Love, I didn't realize that this contrasted with other concepts of God - or that this business of Love actually placed constraints upon what God could or would do (and the reason for his doing it).
The problem was, perhaps, teleology - purpose and goal - what was the purpose of 'reality' and how did that purpose relate to Man? I had never heard that there was anything in Christianity about each Man becoming a (small g) god as his ultimate goal beyond death - I knew nothing about divinization, theosis, sanctification, spiritual progression (except in non-Christian sources which assumed that this was supposed to happen on earth, during mortal life).
My only understanding of what was supposed to be going on in the Christian scheme of things was that God made Man the way he is, then Man fell into original sin, and then God set things back the way they had started out - which seemed a pretty pointless exercise, overall.
If I had known about the theme of divinization or theosis (eg from Eastern Orthodoxy or Mormonism) I would probably have wondered why this all powerful God didn't just make things as he wanted them to be from the very beginning - why bother with a process of incremental progress? And why would this totally powerful and autonomous 'omni' God bother with creating Men - what could he possibly gain from the exercise - given that he had everything and needed nothing?
Therefore, for me personally, the constraints of a limited God - the idea of God conceptualized in very concrete and personal terms as an actual being - spatio-temporally bounded - with a body, parts and passions God wrestling with the stuff of reality to create order, Goodness and raise Men to gods - a limited God who starts with chaos and must create step-by-step what he aims for - a God whose nature of Love also sets limits on what he can do... all these limitations and constraints are vital to me making sense of God, and of Christianity generally: including the need for Jesus Christ.
And this God is not a God of the philosophers, not a God created to explain - he is a God who is a person above all; a person who must become known by ourselves as Men who - as potential and partial gods ourselves, but true embryonic gods - are also very constrained and also liberated (for ill and good) by our own natures. The key concept is God as heavenly Father - with (in an ideal and complete way) relates to us a Father to beloved children; and I see no limt to this understanding - God as loving Father is not just a metaphor to be dropped at some point in the analysis by sophisticated thinkers, but an understanding which goes all the way through.
Strangely, it s the constraints on God which enable me to recognize him as true; whereas the abstract God described as being everywhere all the time and outside of time, the God of infinite power and knowledge... well, such a God makes no deep sense to me: not just because the concepts are beyond human comprehension, but mainly because he is such a total explanation for everything, that in practice he explains nothing.