At an ordinary club, Benitez might do well; but Chelsea aren't ordinary, so he may run into a problem like the one he had at Inter: egotistical big-name players who don't like being told what to do. Before very long, they might be whispering to journalists about 'senior players not understanding or liking Benitez's training/tactics'. In short, he would need an outstanding start in order to get people onside.
This is the main problem of signing Benitez on a short term contract. If they do, there is simply no way they could keep that facht quiet. And so, you have a dressing room of players who know this boss will not be there at the end of the season, ie, he can't massively impact their employment with the club by selling them.
Which would put the Chavs into the sort of position we found ourselves in when SAF announced his intention to retire before famously and happily for us, going back on his initial decision. Its folklore now as to what a huge detrimental effect this knowledge had on our players, Dwight Yorke's demise being the most public manifestation of that.
Im not surprised at all that de Matteo has been relieved of his duties. How he got the job in the first place was a very dubious circumstance, and ECL winner not withstanding, installing him as full time manager at the end of last season was clearly an emotionally driven decision.
But to sack him now, only to replace him with another stop gap, with no cast iron guarantee that a desired candidate will take over in the summer (Guardiola may agree now but renege later; as Ronaldo says 'the future - who knows?'), the choice to sack de Matteo now seems very flawed thinking.
What happens if Benitez comes in, and wins a domestic treble? What is he insists on playing a system of football diametrically opposite to what the new manager in the summer will want to play.
Im sure the Chav board have a master strategy that makes sense to them, but I can't see it yet.