I also prefer Prandelli.
Ranieri wouldn't be good. We arleady have a lot of players fighting for one position, Ranieri is very insecure and will field a different formation every week. True that Chelsea have come far in the CL this year, but with his player material he should have done way better. Insteaf of the team improving though, his rotation system has made most players only worse.
The one player that playes all the time is Lampard, and he has made a very big LEAP in skill/class forward.