Heres my view...
...First of all to begin with, AVB was sent into Chelsea to mix things up and build a squad which can win the Title - AVB went in and was harsh with the older names and it didn't work out, and was fired - but wasn't given a chance to do what he was brought in to do.
Then they bring in Di Matteo, and go back to square one essentially, and keep the older players in and the morale up. They started playing abit better thanks to morale, won the FA Cup and the Champions League - but then Abramovic was put in a difficult position, as RDM wasn't the manager he wanted in charge of Chelsea permanently, but he had just won the champions league, so he can hardly fire him.
So RDM gets fired at the first opportunity, which makes sense really, he was never the guy chelsea wanted.
The Benitez signing does make sense to me, he has won the champions league, managed a team in the premier league, and they could sign him up quick. Its also a big help that Benitez was the manager who brought Torres to Liverpool and had him playing the best football he has played in his career. Abramovic doesn't want £50 million to go to waste! In my opinion he is the perfect manager for Chelsea at the moment, and they have the players to challenge for the league imo - especially if they make a few signings in January like a striker and defensive midfielder.
The only strange thing for me, is the fact Benitez has taken the job. The contract is very short, as soon as Guardiola comes available he will be sacked, and its inevitable he will be sacked within 2 years even if he did get a contract extension.