He greatly excelled in all aspects of his craft and proved himself to be an all-time great songwriter who had a diverse range
If you trace the evolution of his songwriting you can trace individual lines of songs that were sequels or advancement/sequel to a former song
Example - "Temptations", "How Do U Want It", "Toss It Up" . . artists try to establish these types of successful lines of singles so you can recreate a proven product that works with their fan base. Your brand is almost riding on the success of these singles because one year with a bad one will greatly damage the brand and success of future singles in the same realm and you'll probably have to pull it back at least for awhile and maybe come up with another single in the vain a couple albums down the road.
Another example
"Pain" and "Lost Souls"
He went from the disenfranchised oppressed militant from his earlier work to the military leader character that you hear in so many of his 1996 songs, where he sounds like he's plotting an actual war on the song, a level of drama that you'd expect from a film director. You get this type of writing from someone who studied Shakespeare
"Ambitionz Az a Ridah" evolved into "Hail Mary" - the person in conflict with his enemies
Most of the songs in his catalog have a spiritual successor