I see that I'm the only one to vote for Decker. Probably because everyone on the Internet thinks it's going to be a true villain from TOS. I don't. In this article:
He is very ruthless…He is not a clearly good or evil character. He is a villain but the actions he takes has intent and reason.
To me this sounds like someone who wasn't really evil in the Prime universe. Someone who if given the right motivation could go on a rampage but could have legitimate reasons for it.
BC's character wants revenge and is apparently trying to save his family. To many captains their crew is like their family. In The Doomsday Machine, Decker wanted to avenge his crew while also preventing the same thing from happening to anyone else. He wasn't evil, but he wasn't completely good in the episode. To me, no other known villain fits with the above quote.
What do you think?