What about producers? or both?
Anyway,
This scenario happens in all products: art, tools, whatever. There's always a group of people who are responsible for creating it outta thin air, then the people who show up and perfect it. (and of course the people who show up later and water it down). It's a simple life cycle thing.
You could say this for just about any rapper not called Nas, Wu-Tang, Mobb Deep, Biggie, etc.... basically any rapper prior to the mid 90s.
I think rappers should be placed in one of two categories before judging them on a top 5 basis: Pioneer and Perfecter.
Rakim is a pioneer. Nas is a perfecter. You can't really say one is better than the other because they exist in different dimensions.
Regarding 3-6, I'll just copy and paste because I'm lazy:
3-6 Mafia's "dark Memphis bounce" is fukking brilliant. Some super unique shyt. But their songs were shyt for the most part. They reused the same bounce countless times on tracks with no verses. Just chants. That shyt gets boring.
ASAP Rocky took the coolest part (the bounce, maybe a couple chants) and left everything else that didn't work. Expanded on it.
So overall, it's possible for me to be a Rocky fan while not being the biggest fan of his predecessors. It's not possible for me to be a Rocky fan and not respect what his predecessors brought to the table.