I think saturation in rap has always been "over saturated" its something every generation of Hip-Hop has had to deal with at least imo. But I have to agree that the 2015/2016 was amazin! That old Carti had a vibe that is just outta dis world! Acts like Divine Council, Uno, Fauni, etc.. were becoming more established, it was a whole ass vibe I don't think can be recreated :(.
SGP got an honorable mention 4 me cuz even tho a lot may hate him or his music, I feel like his new sound at the time influenced the people I mentioned in one way or another. But nonetheless 2015/2016 was another golden age of Hip-Hop!