Christian got respectable matches out of Zeke Jackson and Tommy Dreamer for crying out loud.
Ever since moving from ECW, he's wrestled Dibiase a few times, Ziggler a few times, got beat in a tag match by Vance Archer and Curt Hawkins, and wrestled Edge to the finest RAW match since the HBK-Jericho stuff. I don't recall any sufficient feuds that went to a PPV, either. He hasn't had a credible shot.
Poor booking is the worst thing that's happened to him. He could be in a great feud with Edge right now instead of the horrid Orton-Edge angle on RAW which is quite boring, and that itself seems so forced. Then again, all feuds do these days (ranging from main events, tag, mid-card, and Divas - limited exposure of a roster will do that, I guess).