Why do many critics find fault with "Of Mice and Men"?

On the whole the book has had rave reviews from critics, especially for use in curriculum, but there are some literary, sexual, social, and political critiques that could be made out of favor with the book. For starters on the literary front, the book itself is very repetitive and it's already short. There is a lot of redundancy in regards to Lenny and George talking about the farm they hope to have someday.

Some critics have also argued that Steinbeck could have done more with Crooks as a character because racial exclusion was such a big problem in the country at the time and with the exception of perhaps the scene in his separate bunkhouse with Lenny and Candy in Chapter 4.