Common trend to the Christian love if you notice "In TNA..." "When in TNA..." He isn't in TNA anymore.
He is distinctively average, he is by no means the worst wrestler ever, but he is never going to have a great match minus gimmicks.
As for Edge, yeah he was the go to guy for a while, in WWE's bleakest period. He has had people with him anytime he has been good, started off with Christian the 2 together, fairly entertaining. Then he was on his own in a very forgettable time, then he was with Lita a heat magnet and the best time of his career, then she left and he was on his own and did nothing again. Then he got Vickie another heat magnet and he got a rub of some of her heat, and he looked good again. Now he is on his own again and is doing nothing noteworthy.