Although it's very late to be changing manager Norwich are in a no lose situation in terms of the media's opinion of the decision. If they stay up it will be viewed as the right thing to do, and if they go down it will be because they have lost the games most people expect them tk lose anyway.
Saying that, you only have to look at the Kevin Macdonald "era" of a few games to see how risky appointing a successful youth coach/manager can be.