I think G'Kar took a few episodes to come into his own; essentially, once Straczynski stopped using him simply as a heavy and allowed for more wisdom and introspection ("Mind War," I think?) he became much more interesting. The same thing might be said about Crais on Farscape
, of course. He's effective in "Premiere," but one-dimensional. He gets some important backstory in "That Old Black Magic" and only grows from there.