Basically we are talking about great defining moments for Spider-Man outside his titles, and in this case, specifically in Avengers books where he's an Avenger. It's not a big surprise that Spider-Man comes of well in the Civil War tie-ins that JMS wrote, as opposed to the actual CIVIL WAR title. It's not a surprise that Spider-Man does well in the Hydra story that JMS wrote as opposed to what Bendis did in New Avengers.
My argument and that of many others is that there aren't enough, not of sufficient impact, to justify Spider-Man being part of the Avengers because what is there to be gained? Nothing for the most part. As a fan of Spider-Man, it's more important to see him defeat Juggernaut on his own than in him being part of the Avengers and being assigned a minor role while other people do cool stuff. The former happens to be a story of far greater quality than any Avengers story with Spider-man. Spider-Man's best showing in any Marvel event remains SECRET WARS 1984. Nothing since then, certainly none of the Avengers stuff, has given anything to write about compared to that.
"shared universe" is pretty hollow because some shares are bigger than others, and some are more equal than others.Does what happens in CAP or Iron man solo stories involving avengers not count it seems kinda dumb it is a shared universe.
In the case of Cap, Iron Man, Thor, they have smaller shares as solo heroes than Spider-Man does, and bigger shares of Avengers than others. So Cap, Iron Man, and Thor have great moments in their own books and great moments in the Avengers books. Captain America gets great moments across the board, in fact two of his most major defining moments, happens in a Daredevil story (Born Again - "I'm loyal to nothing general, except the dream") as well as Spider-Man (The Civil War tie-ins by JMS -- the famous "you move" speech). Thor has many moments in his own titles and as an Avenger too ("Ultron, we shall have words with thee"). In the case of Iron Man one can plausibly argue that his greatest stories as a character have been in Avengers titles and not in his solo books. And that were he not an important character in Avengers, he would not have especial relevance. Whatever the case, Iron Man is canonically junior to Spider-Man in 616 and he should not be tied so much to his corner.
Reed Richards was more heavily involved in that story than the Avengers were (which I looked again recently, only Marvel event story that dealt with a city-wide epidemic, Jonah especially comes off as a great mayor these days). And again it's mainly a Spider-Man story and event and happened in ASM.