Variety is key here. I remember playing Mario Odyssey and thinking about how well the game leverages variety to its advantage, and how easily WoW could do the same thing. As in Mario even just a handful of straightforward mechanics can be rearranged, twisted, and subverted into something novel. Except unlike Mario Odyssey WoW isn't constrained by it's genre; as an MMO it can have elements of action, exploration, puzzle, strategy, even a fucking dating sim if it wanted to.