I would say Iwobi has had a string of very good performances and has shown notable improvement under Carlo, but whatever fits your narrativeDepends how you see it. Bolasie was a very good player who was finding his feet here. A lot of his game is on physical athleticism. Now he doesn't have the flexibility to manoeuvre himself to compliment that style and restricted flexibly so his game is effectively ruined.
Iwobi is average - let's face facts. He has a lit to prove and a couple of games of ok performances doesn't go far yet.