He bowls a decent pace and a very consistent line. Against NEw Zealand he was clearly uncomfortable bowling full and kept dropping too short. When they convinced him to bowl full in the second innings he was over pitching. It is probably a confidence thing. The bowlers in my side always hated pitching the ball up and you had to bully them into it.
If he can sort out his length he can take a lot of wickets. He is definitely different from the standard English trundlers.
THen there are the injuries. Very few quick bowlers have the kind of kneesand ankles that can stand the strain they put on them. People like Curley and Allan Donald are just physical freaks as well as world class bowlers.