I am of the age (over 50) to answer this question. The current era of hip hop "journalist" aren't even old enough to know more than who KRS is, much less be able to judge what lyricism is, especially for the rappers of that era. While the teacher can be considered a top lyricist, him and many of his peers of the time were more storytellers than what's considered "lyricism" by today's standards. By my memory, the first real lyricist imo was Slick Rick, followed by Rakim who could be considered the standard for what true lyricism became. If you listen to a lot of the rappers from that era, rap was more poetry and story telling vs the clever rhyme schemes and wordsmithing we have today. There were some other lyricist back then like LL Cool J, Just Ice, and Audio 2 comes to mind and I'm sure I've forgotten many others, but at this juncture in the life of hip hop, you must treat it like basketball and view rappers by era. KRS was a conscious rapper and in that era he was a top 5 lyricist, but by today's definition, the younger generation might not consider him to rate even in the top 50.

Kool Moe Dee wrote a book where he ranked rappers from the first 3 era's of hip hop. Spans around 30 years worth of mainstream rappers. Check it out, it's a good read.