Everyone has flaws. Aldon Smith didn't get a sack for almost the entire 2nd half of the season. There are few "pass rushers" that you can send out there and they get sacks (Jared Allen, Freeney a few years ago, JPP, and Ware come to mind).
The others have to be in a scheme that takes advantage of their skills, and play off the talent around them. Aldon Smith is the perfect example... he was useless without a healthy Justin Smith.
Mingo can add a dimension of SPEED and RELENTLESSNESS to the front 7, which can disrupt things for the offense and help our secondary.
I'm not advocating for us to take him... but those that think Mingo is gonna go out there and challenge Strahan's record in his rookie year... it won't happen.