Having studied both prospects when they came out I would say that Ndamukong Suh was game planned against more than Clowney was. That's not to say that Clowney didn't create problems for offenses, because he did. But Suh was on another level. He forced teams to design their entire game plans to avoid him, and they still couldn't.
He came onto the scene as a JR with 76 tackles, 16 TFL, 7.5 sacks, 5 passes batted down, and 2 INTs returned for TDs.
As a SR, he was the focal point of every single team's attention whenever they played Nebraska. And he responded with 85 tackles, 20.5 TFL, 12 sacks, 11 passes batted down, and 1 INT. He won the Nagurski, Bednarik, Outland, and Lombardi Awards, and IMO was robbed of the Heisman trophy because he was a defensive player. He was far and away the best player in college football.
I think that is what people expect to see when you talk about a "once in a generation" talent. Double teams, triple teams, chip blocks, you name it. Nobody could stop him.
I recognize the physical athleticism and raw talent that Clowney has. And it is impressive. But "once in a generation" he is not.