Father Skywalker said:

Don't blame Hayden Christensen for the bad acting, blame George Lucas, he wrote the script, Hay Chris just chose to go along with that!!!!!

Check out Jumper and factory Girl, two films he did just after the prequels. His acting is exactly the same level as it is in the prequels in both of those -awful. In fact it's so similar it is as if he is still playing Anakin Skwalker in both of those, except in one he uses a very dodgy accent. Good actors can still shine even with bad directing, but bad actors will still be bad no matter how good the director.