I think there is a sort of thematic feel each type of power system evokes in the reader. The feel I'm going for is that of vulnerability, fragility, or what might be called the "tight-rope" sensation. The feeling of an ordinary human being with as-close-to-ordinary means as possible doing something incredible and death-defying. Achieving something through genuine skill that most other people would shrink away from.
Roland of "The Dark Tower" series comes closer to this, but he still hovers above my mark because Roland is very deadly. He's a warrior in his prime- skills forged over centuries of combat. He's exactly what I mean when I say even a relatively small stacking of relatively modest abilities can still create a being a bit too powerful in ways to where only others with similar abilities can take him down- generally removing ordinary humans from consideration except when they must go to extreme lengths.
The most intriguing thing was King's use of "the touch" which is similar to "the shining". It is not a solid use-at-will power, but more like a ghostly instinct that is ill defined. It gives the person abilities in psychic perception like reading and sending thoughts and seeing or sensing things that can and can't be normally seen. Combined with his lethal physical prowess and it makes a pretty uncanny foe to fight. In a way, I had come to the point of thinking this is probably the best model that can possibly be used. The "fantastic element is already slight" and the physical prowess does verge on the fantastic, but it's still more an aspect of extreme conditioning that over-reach.
The concept I wanted is something akin to a Navy Seal versus NYPD. The Seal is trained to a greater degree and might have better equipment, but he still cannot simply take on a group of armed policeman in a direct police-fight except if he's managed to gain some great strategic positioning. In that example, the Navy Seals considerably higher degree of training still only gives him a slight advantage against other average humans and increasingly less of an advantage as that opposition climbs to, say, Special Task Force units.
It's a game of balance. I'm still woefully underachieved in my writing- basically still scribbling ideas- but nothing to do but keep going. But ironing out your concepts is a good start.