Frankly he needs to stay regardless of another winger or wingback coming in… we also should be exploring for example a 4-4-2 formation which could fit Cambiaso as starting LB and also both Kostic and Iling rotating for the LM spot, it might even work with a 4-3-3 if its an functional one with the right players around him.
However we are just too stubborn on this dysfunctional 3-5-2 to accept the reality that we don’t have the players for it aside from an abundance of CB’s.