Well name some other number two keepers at other clubs, and see who comes out better.
The role of a number 2 keeper is not meant for good goalkeepers, Mignolet and Karius both probably wont stick around long doing it for us depite their weaknesses.
Ok Citeh have Bravo who is better than Mignolet and Karius
Utd have Romero who is better than Mignolet and Karius
Arsenal have Leno or Cech who are better than Mignolet and Karius
Chelsea have Caballero who is better than Mignolet and Karius
Spurs have Vorm who is better than Mignolet and Karius
I could probably carry on but I think you get the picture
BTW I am referring to how Karius is in his current no confidence head fu**ed state, if we was at the level he was when he played for us second half of last season then he'd be an ok #2