Yes. In public relations you never want to trickle out bad/concerning the news, you want to "rip off the band-aid and preferably follow it up with some positive/distracting news like 3.5 Pro model release or price drops.

Isn't it "just" a matter of Jeff Dean (& co) leaving, Hassabis replacing Dean, and Kavukcuoglu replacing Hassabis ?

A massive shake up for sure, but why do you see it as separate events merely timed to coincide ?