I don't really know what people expected out of this guy. He's always been a mediocre manager, was removed from jobs in the past, and doesn't have a flexible outlook on the game. He's a far less flexible manager than Ranieri and in times of difficulty you need to be able to make changes to your own methods. Not sure why one would expect someone like DN to take us back to the Champions League after such a season of disaster, but whatever.
And another thing -- where are all those people that said being eliminated from Europa was good for the side? Just taking a gander at the current events of this team, we have literally fallen off a cliff after being eliminated. I was laughed at for pointing out that we completely fell apart after being kicked out of Europe last year, and that it could happen again. We even have injury problems without playing in Europa (gee, imagine that!). So now we're back on a similar path to last season which needs to be corrected now before the problems become exacerbate.
I'm not prepared to fire DN at this point, especially considering we'd just replace him with someone like Zaccheroni. The latter is probably the better manager but what's the point if he's lost the plot on the game as well. Even if we do pull ourselves together and qualify for Europe, finding a suitable manager for the future should also be on the agenda, as DN surely isn't the guy.