Christenson to me is just average, and sure he was good in Shattered Glass, but to me every actor has that one role to fit them perfectly. If you watch the TV show Higher Ground which was on in 2000, right before filming AOTC, Hayden plays a troubled kid who does the same whiny voice and whiny expressions, and that is cause I believe he is a symbol of alot of actors today, good looks but not much talent. Sure good looks have always been a part of Hollywood, but I feel the quality in acting has surely dropped in the last 15-20 years, and most of the great actors now are secondary actors.
As bad as a director as Lucas has become with the PT, McGregor, McDiarmid, Christopher Lee, Pernilia August, and Liam Neeson all turned in good performances in those movies, mostly cause they are seasoned actors that even though the dialogue is very campy in SW, they can overcome it the same way Alec Guiness, Phil Brown, Peter Cushing, were able to do it in the OT movies.
I think if Lucas would have made Anakin in late 20's, he could have hired a more experienced actor to play him, like an Eric Bana, someone who could carry a movie with those dramatic scenes. I think McGregor is great in ROTS, and when he is yelling at Anakin when he is burning up is one of the few times I got goosebumps, but Hayden/Natalie and their acting in the PT is downright average most of the time, but they are good looking, and that is what sells in Hollywood now.