About the sampling issue: while it is true that sampling has always been a major part of hip hop, I feel as though Kanye always samples a larger part of the original songs in order to make his tracks sound good. He often samples the vocals to include them in his choruses which is sampling more than just sampling to create a nice beat, it's almost like remixing the original song into a hip hop song.
If you take away the famous samples from his singles, a lot of his material just wouldn't be as hot (Through The Wire, Diamonds Are Forever, Stronger, Jesus Walks, Gold Digger, Otis). I'm not saying it's not a skill, 'cause it is, but I feel it just takes less imagination to take an already famous song, sample it for both the beat AND write your lyrics around the parts of the original chorus. Kanye was a breath of fresh air when he came out, but I think his producing career relies on famous samples even more than the average hip hop producer's.
All of the Kanye beats that I like the most, usually sample the vocals from the original song as well. When it doesn't, I often just don't feel it as much and it sounds like it's trying too much to create a new school/futuristic type of sound (especially on MBDTF and WTT) which to me becomes boring very quickly and ironically sounds dated much quicker than the more traditional hip hop beats. But this will vary from person to person of course, according to taste.
Kanye is nice but in my opininon he's not on the level of DJ Quik, Madlib, RZA, Premier etc.
