Kendrick's greatest strength is his songwriting and forming concepts. That nikka knows how to craft albums. His ideas are outside the box, and an exceptional storyteller. That's the main reason he's ahead of his peers.
But it's true that he's lacking in quotables and bars that make you go "run dat back

", this really shows in his feature appearances, which outside of a few notable ones he's usually

on. On a surface level his verses ain't adavanced like a Hov or Lu with the wordplay and extended metaphors/punchlines but he's got a diverse flow, decent rhyme patterns that he can switch up, and he's personable in his music.
Funny enough, out of the three albums, I feel that "To Pimp A Butterfly" was his weakest effort as a rapper (flow, delivery, rhymes, all around performance-wise) but arguably his best effort as a songwriter (GKMC gets the edge from me).