Thing is, they are getting Benitez for his managerial style that is opposite to Ancelotti, rotates, plays balanced, disciplinarian, hard on players, etc, however they'll ask him to change a lot of those things because of the team he'll manage and the players present.
Players also love Ancelotti because he is a player friendly manager. That could be a problem for the long term benefit of the club, having a coach that always does what the players like to keep the happy, like all the problems they've had with fitness and injuries, however to go from that to a disciplinarian, and not one with a pedigree to match both Ancelotti and Mourinho, could very well end up in a complete and utter disaster.
We'll see what happens.