Oh of course. On terms of lyricism, Kanye isn't the best. That's really obvious, and would simply be an insult to people like Eminem and Ab-Soul who have created their entire rap personas around lyrical ability. But on the terms of what is artistry, and what the greatest artists of all time have embodied, Kanye has done this to the highest degree out of any other artist in this current century.

Could depend what you consider 'Artistry' as. He has his art, fashion and movements. As for his rapping, we established that he's not as lyrically adept as other artists. And his movements have only made notice because of his fame(you could argue however, that his fame doesn't negate the purpose behind the movement itself) ... Give his spotlight and following to someone like Eyedea and well... It would speak for itself. And his movements in fashion... Eh! That doesn't constitute to being a great artist. They just seem to target impressionable teens. Plus, it's hard to be considered great when you're an obnoxious dick about everything you can possibly get involved in.

Anything radical can be said to target impressionable teens now-a-days. But the fact of the matter is that his artistic output is at a very high quality, I think almost any professional critique will agree with that. And while with this quality of artistic output, it doesn't mean anything if it's just regurgitating the same thing that other artists have done before. The term of "best" in art implies not only quality, but originality, and it implies a powerful enough influential force to shape the trend of art past it. This is why defined "best" in art is not exactly a walk in the park. But I just think it's so evident that Kanye takes this spot. I mean for example, we can just see the rise in high pitched sample usage after The College Dropout and Late Registration, the electronic rap movement after Graduation, the dip in electronic rap following Yeezus (due to it being so...abrasive on the subgenre) and the rekindling of story driven albums and sparking of new trends given by My Beautiful Dark Twisted Fantasy. To be the best artist I think it logically follows that you must have high quality artistic output (obviously), you must have wide spread artistic output (versatility), you must have originality, and you must be influential on the art itself following your output. As far as artistry goes, I think these objective standards are arguably the most unbiased ones you can go by. If you think of the artists that we call the best off all/their time, these are the factors that they embodied to a higher degree than all others during their time. Kanye is that person from 2000-present.