A harsh assessment, but fairly accurate, except you forgot Rhino, but yeah Kingpin is definitely far and away the best villain in that run. Is it arguable that Kingpin can rank up with the likes of Green Goblin, Mysterio, Kraven, Doc Oc, Sandman, Vulture, Scorpion? What is Kingpins actual superpowers? 50 tho is the most iconic cover in the run from 1-100 imo and arguably one of the most iconic covers of all time, which probably explains its value as much as Kingpins first appearance.
Also 40 was a decent issue