So you set off to create a character along with your fellow artist, and not only is said character successful but you're able to have a great 30-plus issue run with said character. But then your artist leaves despite you wanting to do more, so what do you do?
Well, that was the dilemma Stan "The Man" Lee was facing after the end of "The Master Planner" storyline. Fortunately there was an another artist that could help-John Romita Sr., who had been working on Daredevil prior to this point. Being the "sap" that he was and wanting to get close to paying off his mortgage Romita agreed to take on the assignment. And in this second volume his artistry helps elevate Peter Parker's world to a degree beyond what Ditko had done.
At first Romita tried to emulate Ditko's style but the former found that it wasn't working, and Stan sensed it too, to the point where he told Romita to do it the way the latter felt was best. And it was the best desicion.
With Romita Sr behind the pencils Peter Parker was able to age from a shy nerdy high school kid to a young adult facing all the challenges that a college student would face, as well as the fantastical challenges from his Rogue's Gallery.
Obviously the changes weren't instant, but they did happen over time, and to Romita's surprise sales of The Amazing Spider-Man soared.
Along with aging Peter and his supporting cast a bit, their personalities mellowed out more, as opposed to Ditko's interpretation where everybody seemed high-strung.
And finally, at long last, the idenity of Mary Jane Watson was revealed. While it isn't known if Ditko ever had character designs for MJ, it didn't really matter since what Romita ended up doing, especially with that famous page...well, some masterpieces just speak for themselves.
In addition, Romita joining the book really helped turn Amazing into a true comic book soap-opera, where there are moments where Peter Parker is able to have good moments with his college friends, and then when he's Spider-Man he is dealing with a whole slew of problems from his villains while still trying to make ends meet, not the least of which him caving into giving up the mantle for a short while before coming to his senses.
Speaking of problems, this run is where the Green Goblin begins to transform into more of a threat than what Peter Parker has had to face up to this point, namely being that not only does Gobby know who Spider-Man really is, but audiences finally discover the identity of said Goblin - Billionaire industrialist Norman Osborn. And after the battle it seems like maybe Osborn is rid of the Goblin after the battle, those who know the story know that that change isn't permanent and the Goblin will return.
In all, this run definitely signaled a change in the Spider-Man comics, and in a way that didn't take the character backward but forward and in a time where most comic book heroes didn't grow up all that much this was very significant. More audiences - especially older ones - discovered the Spider-Man books, and it would ultimately become something that some readers would later call "counter-culture" in the years to come given just how different the Spider-Man comics were from everything else and just how much audiences connected with Peter Parker and his world.
So if you haven't had a chance to check this Omnibus out, do so. It's a classic run that does a near-perfect transition from Ditko to Romita, as well as maturing Spidey's world and having him web-sling into a much larger place beyond his teenage years and into adulthood.