Seems about right, my data alone is 114 gb, with the root folder showing 152. But with WoW, the install shares data between all versions of the client, from classic, to retail, from ptr, etc.
Even if the “current” game doesn’t appear to be all that big, all of the data for all of the content that’s accessible still needs to be present. That’s maps, models, textures, shader programs, audio, and thousands upon thousands of lines of text. Considering we’re now 10 expansions in, plus the base game, it’s not unreasonable that each of them represents 10GB or so of data - even factoring in what’s been replaced - leading to an approximate total of 110GB.