Monks are the only baseline class that’s been added to World of Warcraft since the game’s launch – two hero classes have been added on, but Monk is a base class that starts from level 1 like everyone else. The class is also receiving adjustments in Legion like every other class, with the same fundamental goals of trimming up weaknesses and making for more interesting gameplay.
Brewmaster Monks have seen a large change, focused around the idea that they should be slightly squishy when directly hit but experts at dodging and weaving away from attacks. Mistweaver is more focused upon healing now rather than healing and doing damage. Both specs have also lost Chi as a resource, but Windwalkers have retained it, along with a new emphasis on rotating through abilities with the new Combo Strikes mastery. Check out the full rundown of the core mechanics on the official site.