Lal.
The gradual process should have started 3 years ago. If he started gradually you'd remain 3 years behind target, he had no choice to go quick because of the continuing incompetence from the Chelsea management. The Chelsea squad are all adults, I doubt it would have been difficult for them to not throw their toys out of the pram when they're dropped or asked to do something they don't want to do.
RDM hardly had outstanding league form, sacking him did nothing to change your EL course. Yes, you're in the CL now. That's luck rather than foresight, even the most optimistic of Chelsea fans would have struggled to see you qualifying by winning it at the time. We've been through this multiple times, one dud season doesn't set expectations for players. They know your resources, they know your ambition, they aren't going to reject you on the basis of you performing badly one year. Or maybe we should get on the phone to Jordi Alba, since Barca aren't the right club for him if he wants to win trophies.
AVB is far more reputable than RDM, you can attract the likes of Hazard because you won the CL. To say you would have had to do with lesser players with AVB is utter nonsense trying to rationalise sacking him.