How much blame should Andy Weidl and Omar Khan have?

We talk a lot about Matt Canada and Mike Tomlin, but how much blame should Andy Weidl and Omar Khan have for their free agent signings?! Patrick Peterson, Kwon Alexander, Isaac Seumalo, Roberts, Holcomb, Robinson, and Neal all have PFF grades below 65. Allen Robinson is at 54.5! Crowley asks: who's a bigger disappointment, Patrick Peterson or Seumalo? Dorin and Crowley differ on their answers.