Kraven's Last Hunt was essentially a six issue fill-in arc. While it built on earlier DeMatteis stories (especially Vermin's appearance in Marvel Team Up) and did have a follow-up in his Spectacular Spider-Man run, it was self-contained.
The Night Gwen Stacy Died was part of a larger run, although it was rather accessible, partly because some ongoing subplots (Aunt May essentially being Doc Ock's prisoner) were ignored.
I thought Wolfman's run got really good in the second half, when he had that Spider Slayer two parter. Then came the Black Cat's first appearance, the final fight with the Kingpin, the return of Mysterio and the Burglar's story.