Raji has had his motor questioned, but I think his on-field results are at least 75% due to his role in the scheme. Both he and Dom have said that the job of the base DL in his 3-4 is to "keep the LBs clean." That's tough to judge without looking at the tape, but we know it's not fair to judge these guys on football card stats.
I'm actually cooking up a post on the defensive scheme that will elaborate.