He had back problems and we all know what that can do to a player. I've said it several times but he looks way more lightweight than before, there isn't much in his game whatsoever. Players can just smack him around and he's not moving well.
Yeah, he has transitioned to a much more patient game. First career was your stereotypical Russian player, big flat hits being the signature, but since the last big comeback he was much craftier and patient, often quite defensive. Not that easy to maintain such a game year round against power as he gets older, he is 29 next month after all.
Maybe needs to make a third version of his game, a mixture of the first two.