Yknow what the most depressing thing about
Heroes is for me? That I can distinctly recall answering a thread like this before that series debuted, and described my ideal series being exactly like
Heroes, only set in the near future and with scientifically plausible explanations for the powers (and having powers more like "enhanced intuition or intelligence" rather than comic-book derived superpowers).
So that's what I want. Maybe
Gattaca could be that show? Sorta taking the opposite direction with the material that
Heroes did.
Or: civil war between Earth and an Earth colony in the Solar System, preferably Mars. What could be cooler? I defy Hollywood to frak that up!
Or: something I wouldn't think of on my own in a million years.
Lost is the best example of this. Obviously, this is difficult to describe in detail but I'll know it when I see it.
How about a series(realistic) about a colonized Solar system. Titan, Mars, Ceres, etc all have thriving, established colonies with their own political and social conventions.
I remember a fascinating comic book with characters from each of the planets, all genetically engineered to fit their particular environment. It's crazy to imagine what adaptation could work, say, for Venus, so the planets would have to be terraformed to meet the genetic engineering halfway - maybe there's a way to make Venus livable for some variation on humanity, if not the ones inhabiting Earth.
Think Dexter, with tentacles.
Dexter is the most convincing depiction of a inhuman mentality I've ever seen on TV. How ironic that it's not even sci fi.

(I think of it as "honorary sci fi.") I'd love to see a show dispense with the notion that the aliens, mutants and robots must be metaphorical humans and attempt to create a protagonist - not a villain, that's too easy - with a truly alien way of thinking.
But they'd mostly rely on really good characters
Every story depends on really good characters, so that's a given. Also competent writing and acting, and production values that don't make you laugh. There are many ways to take a great idea and utterly destroy it, which brings me full circle to
Heroes...