And those were casting mistakes. Denzel is a favorite actor of mine, but he really did not read Shakespeare well, IMO. Keanu Reeves was awful, and Michael Keaton was not funny in one of Shakespeare's funniest roles (Dogberry).
Branagh likewise made casting errors in Hamlet with Jack Lemmon godawful as Marcellus and Billy Crystal and Robin Williams adding nothing to the proceedings, either.
Branagh seems to think such casting will bring in more non-Shakespeareans. All he does is bring his films down when he casts people who are wrong for their roles. You are correct that this type of casting is nothing new with Branagh. Looks like he will make similar mistakes with this new Thor film.
I agree that Keanu was awful and Keaton was off as Dogberry, but Denzel was terrific! If you don’t agree that he was good, we are going to just disagree on that point forever.