In the pecking order of spokesmen for atheism, or secular philosophers in particular, Paul Draper is one of the better representatives. So this is a window into the mind of a prominent atheist thinker:
More importantly, if theism is true, then God is not only morally perfect, he is omnipotent and so could make many different sorts of intelligent life, probably infinitely many, including intelligent beings that are much more impressive than human beings. On single-universe naturalism, by contrast, one would expect that, if there is intelligent life, it will be relatively unimpressive. I want to emphasize the word "relatively" here, because I am not denying that human beings are impressive in many ways. But examined from the perspective of what is possible for an omnipotent being, we are, in terms of intelligence, a hair's breadth away from monkeys. Again, one would expect this on single-universe naturalism because the more intelligent the life, the less likely it is that naturalistic processes would produce it. Of course, if one believes in God and, looking around, finds nothing more impressive than human beings, one will be forced to conclude that God wanted to make beings with very limited intelligence. But surely one would not have predicted this beforehand. There are indefinitely many different kinds of creatures that an omnipotent being would have the power to create and that, other things being equal, would be more valuable to create than humans. Antecedently, a God would be more likely to create these more impressive creatures than to create us.
One might object, however, that a good God would not be obligated to create the best and that a loving God might very well want to create and love inferior beings like us, especially since that doesn't preclude his also creating other more impressive beings. I don't deny that a God might create beings like us--that is certainly possible. Similarly, Collins admits that fine-tuning is possible even if single-universe naturalism is true. The issue, however, is what is antecedently likely--what a reasonable person would expect beforehand. And human beings have many features that make them an unlikely choice, no matter how many other sorts of beings God creates. This is especially true, if we take the term "human" not merely in the biological sense but in a fuller sense that implies some of our most notable and notorious characteristics. In this sense of the term "human," the sense intended when someone says "I'm only human," being human implies being naturally selfish (not to mention territorial and aggressive), which greatly limits our potential for developing morally, especially given our limited life span. It also includes the fact that we are profoundly ignorant beings, especially when it comes to moral and religious matters, as is obvious from the fact that we disagree or are uncertain about many important moral and religious issues. We also naturally identify with others that we perceive to be like ourselves, leading, if not always to prejudice and intolerance, at least to isolation for those different from the norm. (I could go on and on, but it's too depressing.)
i) Draper is like a grown child who complains that his parents wronged him by conceiving him. He didn't consent to exist. He didn't give his parents permission to conceive him! Draper is a self-hating atheist. The existence of unimpressive humans like Draper is evidence that God doesn't exist.
Of course, that's a bit of a paradox. If God made more impressive creatures instead of humans, then humans like Draper would be in no position to complain about how unimpressive they are, since they wouldn't exist in the first place.
ii) Then there's the standard of comparison. Impressive to whom? Valuable to whom? Since any creature God made, however great, would be infinitely inferior to God's surpassing greatness, God can't be impressed by any creature. It's nonsensical to say a creature could be impressive in relation to God.
Valuable to whom? Well, most humans value their own existence. Most humans value other humans.
iii) Apparently, Draper means impressive relative to some hypothetically greater creature. Even so, why should God care about that? Since any creature will be unimpressive by God's standards, we're talking about a pecking order of unimpressive creatures, where, at best, one unimpressive creature is more unimpressive or less unimpressive than another. Hard to see how degrees of unimpressiveness would single out any candidate for existence. "Sure, I'm unimpressive, but you're even more unimpressive!"
iv) Draper's objection is equivocal. A creature can be more impressive in one or more respects than another creature, but less impressive in one or more respects. In some respects, many major predators are more impressive than humans, but they lack our intelligence. Likewise, many creatures have sensory aptitudes or acuities that we lack, but we're far smarter than they are. How disadvantages in one respect are offset by advantages in another respect is part of what makes animals interesting. Humans are very weak creatures compared to so many other animals, yet we're the dominant species.
v) This also goes to the issue of tradeoffs. No one creature can combine every superlative excellence. Some abilities exclude other abilities. Take the ability to fly.
Or consider the human brain. It's already so big that it makes childbirth difficult. Moreover, the size of the brain must be balanced out by other physical requirements, like blood supply. If we had larger lungs, we could run faster for longer, but that would require other compensatory adjustments. And so on and so forth.
Moreover, humans are a package. To do what we do requires a combination of brainpower, bipedalism to free up hands with fine-motor abilities, and front-facing eyes to coordinate eye-to-hand calibration. If we were quadrupeds, we'd be faster, but our superior intelligence would be frustrated by a body ill-suited to our intellectual abilities.
vi) In addition, humans are earthlings. We share a planet with many other creatures. It would be incongruous to have a world in which one species is incomparably more impressive than all the others.
vii) Draper's criterion is atomistic. The standard of impressiveness isn't simply individual organisms, considered in isolation, but the sheer variety of creative strategies on display.
viii) Draper fails to distinguish between creation and the Fall.
ix) Draper commits a common mistake with respect to omnipotence. If an omnipotent God uses natural means, then that limits what he can do. That doesn't mean he's limited to natural means. He can often bypass natural processes to produce a particular result directly (although even that's not true in the case of second-order effects), but if he's making physical organisms, if he's making a physical world in which things usually operate by a natural process of cause and effect, then that's a self-imposed restriction on his field of action.
x) It's possible that our far-flung universe does contain more impressive creatures than humans.