here's a good example. Denzel has always been pretty well-regarded as an actor with enough talent and charisma to carry a movie by himself. But he is always the same guy. *EXCEPT* in 2001 (Training Day) he portrayed a very different type of character from his norm, and he was rewarded for it by winning the best actor oscar. So talent is one thing but diversity is definitely another
Same could be said for a lot of A-list actors. Leonardo DiCaprio is another one that many people regard as great, yet he plays very similar characters in several of his movies.
Way different cases. Denzel has the same ticks in all of his movies, from Malcolm X to Remember the Titans to Training Day. Everytime he hears something he doesn't like, he turns his head quickly to the side while scoffing. Seriously, he does it as every character he's ever played. And he always gets really still when he gets mad, and stares at you. Leo plays similar characters while still making them so different from one another. He doesn't have the same ticks, and they just seem like completely different people. I feel like if you picked up Coach Boone and made him into a personal security guard that lost his family, he'd be Creasy Bear.
You know who's really good at playing similar characters yet still making them completely different? Tom Hanks.