There are a lot of names there, but the input they had on the record was little more than bits and pieces here and there. I'd say it was probably an 85/15 split.
Okay, so take "I am a God", which is listed on Wikipedia as having 15 distinct writers. (Funny how you were claiming before that Kanye "writes all his shit".) So Kanye wrote 85% of that cut and the other 14 each wrote ~1% on average? What exactly are you basing that 85/15 figure on?
The important thing to understand is that Hip-Hop writing is a largely collaborative process, and has been since its inception. You could use the example of early hip-hop block parties:
The DJ spins a break for rappers to rhyme over, so DJ & Rapper = 2 writing credits there. Bearing in mind that the DJ is most likely spinning pre-recorded music, and also that he would be using two decks with two different songs playing in order to make the 'new' beat, we could conservatively estimate that the between the two decks there are a total of, oh, say 8 writers, making the total number of writers 10.
Now lets say someone at the block party comes up with a cool hook to put on the track. You gotta give that guy a writing credit. So there's 11. Then lets say some musicians want to start jamming along with their own parts, you could then add another 4-5 credits to the track. 14-15 writers?
That's generally how things would work in the studio too. Looking at the specific Kanye track you pointed out I can see that 4 of the credits are from the samples being used, 5 are from musicians/producers who played on the album. The other credits you could probably put down to dudes being around in the studio while they were recording and maybe contributing a line or two but I dunno they could be totally ghost written lyrics and Kanye's name could just be at the top cos he's the boss who got em all there - it wouldn't be the first time that's happened. If they are ghost written, then that was probably a waste of money because those lyrics are terrible.
I get that a lot of people just hate Kanye for who he is and that's fine, I think he's a fucktard too. But to denounce his music just because of that is ignorant. I don't disregard Appetite for Destruction because Axl's a vindictive little bitch and I don't hate Metallica just because Hetfield enjoys a canned hunt. Music is music, if it speaks to you then cool if it doesn't then don't worry about it. jesus.