What is Joe Bloggs going to do with crap like Klassen, Williams and Sandro that Koeman did not do? Hey, I am the new boss and I command want you to suddenly become PL standard players cos I tell you to?
They will hopefully have an arm around them and be coached and mentored to build their confidence back up. The job a manager should do and a job that evidence suggests Koeman didn't do.
They aren't bad players.