Biggest issue with the MCU in general is that they got away from what made A1 and IM1 so good, namely heroes who are likable and enjoy being heroes. The whole emo "I wish I didn't have this burden my life sucks" trope (played out to a Creed like soundtrack for the kegs of the world) has gotten old. SM:HC was a step back to that kind of fun movie again, where the characters meant more than the action. SM2 had the emo issue, but it also had lots of solid character arcs. CW had like one giant awesome fight in the middle and .....? It was basically Marvel Misunderstanding the Movie, but still better than Avengers 2.
The other thing is that the MCU movies have been lacking descent villains since Loki in Avengers 1. I mean, actors in those roles aside (and Keaton dominated this movie), a good central arc with a semi-relatable bad guy who poses a credible threat to the protagonist while also interacting with them is what separates the great comic book movies from the lesser ones. Guardians could get by without one, because it was more of an ensemble comedy in space kind of movie. Cap1 and 2 had menacing iconic enemies with good actors behind them. Avengers 1 had Loki. This movie had Keaton just chewing it up on screen. Meanwhile, Avengers 2 and CW the heroes basically caused all of their own problems or outright created the second rate villains. Most other mid era MCU movies have also had largely phoned in or otherwise weakly executed villains (Ant Man, Dr Strange, IM2, Thor2) which was further exacerbated by most of them also being origin stories, which most of us are sick of at this point. IM3 went the extra mile in trolling by actually teasing Mandarin and shitting on our hopes. A major reason movies like SM2 and Dark Knight have aged so well is because they had well acted and executed antagonists who had descent screen time, including dialog with the protagonist. This, more than anything else, is the main weakness of the MCU movies and I especially like this movie because it directly tackled that issue head on in letting Keaton be as big a part of the movie as Spider-Man.
Ham fisted SJWing aside, this movie did everything absolutely right. It was fun. The main characters were all mostly likable/relatable. RDJ got used sparingly and perfectly. The kid was just being hyper and a kid. No origin story bullshit. Awesome bad guy. No emo horseshit. Humor was spot on the entire way through. It even regularly poked fun of the entire genre in various ways (guy in the chair making fun of every CW show, upside down kiss joke making fun of SM1, ect). Its only flaws were in how some of the action was on screen (amplified in IMAX or 3d) which is sort of a tough issue for portraying Spider-Man if you don't want to do the Guy Ritchie slo-mo bullshit all the time (which the Raimi movies already tried with mixed results). That's entirely forgivable for me, because Spider-Man is not a galaxy saving guy, he is the friendly neighborhood boy scout guy and the action is always going to be second to the humor and story with him.
I put this movie close behind Guardians 2 and solidly above WW for my favorite movie this summer. I think if I am being fair, its probably on par with SM2, given that SM2 was done almost two decades ago and the pop culture created a different atmosphere than this one. The new Spider-Man is a definite step up from Toby. Nappy one name girl is about as terrible as Dunst, so treaded water there. I really like Molina, but Keaton was better. This movie was also more fun, but SM2 was much more true to the comic book I grew up on.