If you want to know how James can do in the NBA, watch Jameer Nelson. He is the most similar player to James in terms of style, body-type, and athletisism. He isn't a star yet, but this will be a break-out year for him.
Also worth comparing them in terms of predicting James' draft position. Nelson was the college POY but went 20th overall. NBA GMs are hesitant to take 5'10 players, even though they often look stupid later on for having passed over them.