Carlsen is by far the world's strongest player, but his results over the last 3 years or so were not as dominant as 2010 to 2015. Mostly due to playing really odd lines due to boredom and overall playing less in general. I tend to be of the camp which believes that the player who will dethrone Carlsen as world champ is still an unknown, younger player. None of the other top grandmasters can beat him over a long-form match.