Really interesting that there's seems to be an optimal amount of words, and some of the most popular such as Eminem and Tyler the Creator are right in the sweet spot. Those that use a smaller vocab like Wiz Khalifa and A Boogie wit da Hoodie are more about emotional content, while those who use huge vocabs like Jedi Mind Tricks and Del the Funky Homosapien are more about getting a message accross. And Aesop Rock and Busdriver are just freaks of nature.
Also, I'm really curious where Pharoahe Monch would fall on this list.