Of modern mainstream artists, Kanye West is definitely the peak. He's shown an understanding of songwriting and music that surpasses many more "artful" underground musicians. He has redefined and reshaped Hip Hop and American culture at large in a way that few musicians have, with the same creativity and prescience as the Beatles. Orthodox critics laughed at Kanye when he wore skinny jeans, released an album with minimal backup, almost no rapping, and heavy autotune, and rapped about subjects that no other 2000s artist would dare touch. But they stopped laughing when every other rapper did the same thing as Kanye, three or four years later.
When looking at his bare musical talent, I think that Kanye is certainly close to the equal of Marvin Gaye, Hendrix, and Stevie Wonder. But it's honestly too soon to tell. Despite having at least eleven years in the industry, Kanye West is at the top of his game. His last two albums were his best, and although his post-Yeezus work has been a little bizarre, nobody knows if he has peaked or not.