No Black Characters

Pulp Fiction, Jackie Brown, Kill Bill, Death Proof, Django Unchained, The Hateful Eight.

..all had significant black characters.

Reservoir Dogs and Inglorious Basterds did not have ANY black characters. (Though Sam Jackson made a guest vocal appearance as a narrator in two scenes in Inglorious Basterds.)

The presence of black characters in QT movies allows for his use(mis-use? abuse?) of the N-word. (And it is used a lot by bad white crooks in Reservoir Dogs.)

But Once Upon a Time in Hollywood has no black characters, no "N word," not even Samuel L. Jackson as a guest narrator (what if HE, instead of Kurt Russell, narrated the third act of the movie?)

The result: possibly the least controversial film ever made by Tarantino.

That said, the critics DID go after the "Bruce Lee scene" for its treatment of an Asian character, and DID go after the finale for "brutality against women." (That they were women who, in real life, stabbed pregnant Sharon Tate multiple times despite her pleas to at least spare her unborn child...didn't matter.)

Still, and even accounting for its violent finale(its joyous, hilarious, exhilarating finale), this is probably the most "nice" movie Tarantino has ever made.