The reason the Blacklist is interesting, is largely because Reddington is a nuanced character. Tom used to be, too. Unpredictable, mysterious, you couldn't tell what side he was on at any given moment, kind of a sociopath, unafraid to kill anyone, good or bad. A real anti-hero. By turning him into a straight up good guy, then giving him a starring role, I think they have diminished his character. Solomon is more interesting than he is.