I'd want to start by referencing Zak S. on this specific issue: http://dndwithpornstars.blogspot.com/2009/10/where-action-is-part-2-grognardia-jack.html
. That post does (albeit with some grumpy throat-clearing about "story gaming") an excellent job pointing out that it's possibly a little backwards to boil down the "Appendix N" feel to a specific set of story beats or background world-building that the right stories share.
Still, I think if you take your points to a higher level of abstraction, you can get to things a little more easily.
I'd say it's not that characters aren't superhuman, so much as they're recognizably human-their ambitions are human-scale, even when they're interacting with grand metaphysical forces (or maybe even especially so)-I'm thinking Fafhrd & the Mouser facing Death to get over their grief, for instance. They're also genuinely flawed.
Similarly, the point about magic is that it's not a technology (de Camp & Pratt notwithstanding). It breaks and burns and has nasty consequences for everybody involved. It always creates victims-I'm thinking about Yag-Kosha or teh crazy old guy in "The howling Tower" here. Even when it's allegedly whimsical.
Monsters, again, are often the same way. They are perversions, abominations, atavisms, but rarely just 1d100 cannon fodder.
But all of this brings me back to Zak's point-that all of this can be seen as an extended inquiry into which different means of problem solving work or don't or fail interestingly in a world where everything is stacked against the everyday working-stiff mercenary or the tough young hustler or the punk kid who thinks she can actually deal with demons and win.
Just my 2 cents-None of it explains the cleric.