Just a random thought:
Let's say DC said to you "Pick someone nobody gives a damn about and update the hell out of it! You got a four issue miniseries to do whatever you want, but don't directly contradict canon. And it's gotta fit within the normal DCU, you can't just go reinventing the wheel by calling it an Elseworld."
Who do you pick? Why? Any idea about what you'd do, specifically, that you wanna share?
If "D-list" isn't specific enough, let's say it can't be anyone who is appearing regularly in a comic, never carried a solo title for more than thirty-ish issues, and no one who has ever been a lead or co-lead in larger media.
And four issues is all you get. DC won't invest more in the project under any circumstances.
Me, I'd pick Amazing Man. I've always thought that character was full of incredible potential. Great name and costume with a retro flair, great powers you don't see very often, and the family/legacy element opens up so many possibilities. You can pretty much point at any aspect of Amazing Man and immediately see three ways it's already cool and five more ways to make it even cooler.
I'd use the character to explore the everyday, "middle class" superhuman experience. The people who have telekinesis but don't fight (or commit) crime, but just like....work at the bank. We'd also look at what it actually takes to be a hero, the knowledge and resources required, the particular brand of crazy you have to be to take the law into your own hands and force your views of justice on the world, and the price that goes with it. More introspective and Vertigo-esque than your typical superhero comic, but still with enough superhero elements to (hopefully) satisfy the core DC readership.
My four issue mini would introduce a new member of the Everett/Clay clan who'd be our new Amazing Man. We'd learn that the WWII era Amazing Man was not the first member of the family to have powers and that their history stretches back more than two thousand years (without artificially increasing their importance to the world, that sorta thing needs to be earned). I'd expand on the powerset by introducing the other-dimensional realm of the periodic table, something sort of like the speed force, but with actual rules.
I'd also piggyback an update to the Power Company on this and have our new Amazing Man work there. But not as part of any security or bodyguard force.
Then the murder of the previous Amazing Man, Markus Clay, forces our new guy up against someone who's been radicalized by superhuman concerns. Obvious parallels to some real world stuff in there of course, with more than a dash of Robinson's Starman in there too.