That's a very solid point you make about To Pimp A Butterfly! It is an album that appeals to everyone, whereas Voodoo doesn't! I agree to that TPAB is extraordinary in that it has banging lines/bangers, but has a deep story behind it!
Back to D'Angelo's Voodoo though, Devil's Pie, the second song on Voodoo, is incredibly different to Playa Playa, the first song on Voodoo. Devil's Pie is a meaty, dull, frustrated, boom-bap, hip-hop, holy kind of track whereas Playa Playa is very atmospheric and soulful and doesn't have that irritated tone or hip-hop/boom-bap' element found on Playa Playa.
Then the third track - Left & Right - is a completely different song again! The playful, fiddly, shuffling guitar melody on that song is catchy, and you have guest appearances by Method Man and Redman on the track too! It's a dizzying song even though it sounds quite straightforward!
Give the album another shot, I think you might end up loving the album Dukey! It's a very immersive, indulgent album so it's not for everyone!