Edwards is an average bowler, and its unlikely he will ever be anything else. His overall record is poor, however, with Edwards its important to consider that he does bring an X-factor to the side that is very important and makes him very unique. When Edwards is good, he is damn near unplayable and we all know that he has spells where has made made some of the best batters in the world look clueless and hop around. However, these spells are more or less balanced out by spells of mediocrity where he bowls with little direction (which is typically the case with Slingers) and/or brain power. But the important point is that he, like Malinga from SL, offers something different to the rest of the side and this is why Lara was always a huge advocate for having him in the side while he was captain..
Getting back to Mahmood, there is no point comparing him to Edwards because Edwards regularly bowls at or above 90mph. Mahmood, has only displayed this ability when the stars are aligned in this favor and we all know that by and large he was mid-high 80s. This isnt going to trouble anyone when there is little direction involved. If Mahmood was a Shaun Tait, I would say bring him in the side. But, when we have Harmison, Flintoff and Anderson who are all just as quick and quite a bit more skillful this seems rather pointless.