Christian is more Evil than Good

Christian deliberately raised Jack to lack self-confidence. What Good Parent would ("White Rabbit" - 105) tell a child: " Don't choose, Jack, don't decide. You don't want to be a hero, you don't try and save everyone because when you fail … you just don't have what it takes." ? Granted, this may have been Christian’s well-meant attempt to "toughen" Jack up, but if so, it achieved the opposite. To me, it looks like a deliberate attempt to cripple Jack emotionally, to prevent him from becoming a Great Leader.

To be fair, it seems that in later life that Christian did try to be a Better Father:
advising Jack to give his patients a little hope, admitting (on Jack’s wedding day) that he wasn’t as good a father as he could have been, advising Jack not to "cross the line" with Gabriela and then, when Jack did so anyway, to "let go" of Sarah.

Nevertheless, Jack, upon arrival on the Island, was riddled with self-doubt and it was only because of Locke’s subtle guidance in "White Rabbit" (not to mention his rescue as Jack dangled over the edge of that cliff) plus the Island’s Healing Influence that Jack gradually grew into his Leadership role

Christian was an adulterer - including fathering a child with his lover
Christian suggested (in "Par Avion" - 312) to Claire that he could stealthily murder Carole (while in her coma):
CHRISTIAN: Claire, your mother is alive, but she’s not really living ... now may be the time to look at other alternatives; other ways to relieve her pain. Now, it is illegal to turn off her machines, but I know of ways that can achieve the same effect without the legal consequences.
CLAIRE: You think that just paying her bills makes you noble or something? You come down here and you try and get me to kill her?
CHRISTIAN: Claire listen to me. Do not keep your mother alive for the wrong reasons. Now there is hope and there is guilt. And believe me, I know the difference.
Note that it was only because Claire refused this "help" that Carole survived, recovered from her coma, and flew to LA, possibly taking over from Kate as Aaron’s Parent figure

Christian was an alcoholic - who basically committed suicide by drinking himself to death: "The police found him in an alley in Queens Cross. Now, a tox screen showed a blood alcohol content, which for a man of his size, probably brought on myocardial infarction - a sizable, and fatal heat-attack." ("White Rabbit"). It may be that having chosen death by suicide, that Christian was resurrected on the Island as a Bad Guy.

In "Meet Kevin Johnson (408)", "Christian" casually, almost gleefully tells Michael that he "can go now"

"Christian" tells John (in "Cabin Fever" - 411) that he is not Jacob but can speak for him
"Christian" subsequently implies (in 505) that he is Jacob and suggests that Ben is an untrustworthy weasel

If Christian does, in fact "speak for" Jacob, there’s further evidence to support Christian’s Badness:
Good Persons like Sayid, Kate, and John are not on Jacob’s List because they are "flawed" - "frightened, angry and weak". People who are on Jacob’s List presumably include Danny Pickett (hater), Colleen (hater), Bea and Mikhail - who cheerfully killed colleagues Greta and Bonnie as well as Charlie.