The Governor – The Walking Dead
I will start this off like I start all my Governor rants. This dude was way scarier and way more fucked up in the comics. But with that elitist shit out of the way, I can honestly admit that he was well-written on the show and brought something very interesting to The Walking Dead. As much as we have seen the characters on that show get stripped of their morals and humanity, The Governor is someone who lost everything, and his mind, in the process.
There is even a book called The Rise of the Governor that does a great job at explaining his backstory WELL before we see him in the comic or show, and if they just adapted that and stretched it out, they would have an opus. It would be a good guy who made promises and had hope, and over the course of many seasons and many losses, he would end up sort of being like a far more psychotic version of Heisenberg from Breaking Bad. A man at the end of his wits, with little left to lose.
Keep in mind, I know we are getting a Walking Dead spinoff. But the fact is, we just know very little about it right now, so speculation will do us no good.
As a quick side note, though, I think that the new spinoff should be told from the viewpoint of the walkers (as if they still had fully cognizant minds). That would be amazing. Seriously, someone hire me to write your f*cking zombie show. We will change lives together.