Rookie Year: Athletic Runner, use his athleticism to get in the passing lanes, and to get penetration to keep defenses honest. Check.
Sophomore Year: Bosh gone, someone needed to step up. It wasn't Bargnani, it was Derozan. A huge Point-per-game average from 8, to 17 points a game. Not to mention the mid-range jump-shot was his bread and butter, after not having any capability to shoot from ANYWHERE on the floor.
3rd Year: High expectations, and quite frankly, did not live up to it. He was inconsistent, with having 2 consecutive games of 20+ points, following the next 3-4 games with single digits. Not to mention that year was the most one-dimensional he's been. Although, he was a diamond in the rough with explosive numbers vs. New York, and New Jersey. Also had wonderful games vs. The Miami Heat.
4th Year: So far, has been a pleasure to watch. Grown in every aspect of the game. His ability to score now looks effortless with the different options he could go to; post-up, off the dribble, better % shooting from outside, and the constant penetration. Not to mention his defense has improved, and the ability to find people, get on the boards, and let the game come to him as improved significantly. Much more skilled, improved, MATURED player.
I don't know, Derozan isn't a real star, who makes the all-star game just after 3-4 years after being drafted, but he's working himself up there.