Right, but it's a moot point because he does have that speed. As long as he has the speed, he'll survive playing CF. I'm not saying he's better defensively than Anderson, but saying he can't play CF because he relies only on speed isn't that great of an analysis. He makes the outs, that's all that matters. However, his speed can't help him on the more difficult plays (like the flyball in Seattle that he misjudged by about 5 feet at the wall). That's where good jumps help you. But he makes the routine play, and he can do it quite well, with the occasional diving catch.
I must say, his arm sucks though.