currently nobody and chichoo are sharing the role of IGL, they've shared that this has been far more comfortable for them. Chichoo has fit kind of into a secondary caller role anyway for at least a year now. On maps where nobody plays yoru it's likely chichoo takes over some parts of the midrounding. Smoggy has learnt the most roles out of everyone on EDG so it makes the most sense to keep him on flex, he probably hasn't learnt Yoru as much as Nobody has. Maybe in the future with more time/practice we could see Smoggy yoru, but regardless it seems the team succeeds the most when Nobody gets to play his game style - that's why you see him lurk so much