In this summer of hip-hop, I've given some time over to wondering why exactly it is that '89-'94 (or so) rap is so much better than everything that came after, Biggie and Jay-Z and Kanye notwithstanding. The best answer I've come to is that the '89-'94 people were image- and message-conscious, but, also being the first wave to deal with rap's massive success, also had a necessary element of introspection. Thus De La Soul, who found a powerful and symbolic conceptual framework for their rapping--D.A.I.S.Y.*--and then spent the next few years worrying over the implications of being associated with that very concept. "It Ain't Hip to Be Labeled a Hippie" and "Brain Washed Follower" may lack the bite of De La Soul is Dead, hip-hop's great concept album, but they're still impressive in their own way.
*And, let's not forget, naming their breakthrough album after an obscure-ish Johnny Cash song.