Oden's second year was cut short by injury, and he had barely seemed to get into a groove before he went down. However, statistically, he had one of the most outstanding sophomore seasons among centers in the NBA over the past thirty years. The bottom line is that, statistically (on a per minute basis which ignores his injury and foul problems) he was competitive with Shaq, Robinson, and Hakeem -- the all-time great centers of the last 3 decades -- ranking above them in many stat categories important to centers. He was significantly better than Howard.
I went to basketball-reference.com, and searched for 2nd year centers since 1980 that played more than 20 games and more than 20 minutes/game. There were 211 players on the list.
I looked at advanced stat categories that you want a center to do well in:
The tables below show how Oden ranked, as well as how the all-time great centers -- Shaq, David Robinson, and Hakeem -- ranked in their second seasons. I also included Dwight Howard as today's greatest center.
Table 1: Oden and Other Great Centers Ranking Among 211 Second Year Centers