I haven't read the comics, but I know about Negan from reading TWD forums. That guy looks like a good fit. Earlier, they were talking to Kevin Durand of "The Strain" about the role, but he decided against it because he was already obligated. I think he would have worked well, but I'm glad that he's staying with "The Strain"; I like his character, Fet, very much.
I agree. And I'd hate to see Fet evil!