Ghost writing in hip-hop is lame and unacceptable for most artists. Dr. Dre, Puff, and Kanye are all famous for using them, but they're all producers first. Kanye is more of a borderline case, because I can see why people would perceive him as a rapper at the point more than a producer.
Dr. Dre was basically a performer. Puff too. So no one was really looking at them like writers. When Dre did 2001, it was an event, and everyone understood that Dre got help. I don't even know if I can put into words why that feels acceptable, but it does.
If you're a rapper first, and rhyming/emceeing is your thing, like Drake is known for, it's not the same as Dre or Puffy using ghostwriters. Drake also (love him or hate him) is one of the last mega stars in hip-hop that is known for being able to rhyme really well. When something like this comes out, it cheapens things.
Hip-hop is one of the only art forms where it's of such importance to the listener that your words are your own, and accurately reflecting your experiences. I don't know. The thing is that Drake is good enough to not even need ghost writers. Just use your own pen. He's a pop star but he's still a rapper first.
