Part of his problem lies in the faceness of his character - Christian NEEDS to be a heel, a selfish, smartass cocky heel. he's just too bland as a face, he's just "Oh I left the WWE cause TNA is awesome" and that's not much to build a personality on.
A few shoot comments from Christian is all that is needed. Looks like TNA took a Jericho clone and made him into a boring Malenko clone. The cookie cutter face of "I only care about is being champion" shit helps no one.