Kendrick is doing something completely different though, he's not putting together tracks with the goal of having the most amazing flow or the most powerful one-liners, he's a songwriter and a story teller.
Anyone that has listened to GKMC should realize this - the album is filled with amazing stories, recurring motifs and themes. Its really a beautiful piece of work.
Rocky is really sick, he has amazing flow, but his album (as a complete piece of work) just doesn't have the intricacy and cohesion that Kendrick's work does. I'm not saying one or the other is better, but you need to realize that kendrick wrote an album, and rocky wrote a bunch of REALLY sick songs.