Angst? What Angst?: The destruction of the Ultimate Marvel universe means that, other than the handful of characters that the Molecule Man saved for him and some other canon imigrants, everybody else he had ever known (or just everybody else, period) ceased to exist. He has never been seen worried or troubled by that. However, some comics imply that in the cosmic retcon he lost his memories of all of that and just thinks that he has always lived in the prime earth, and in others that he still remembers it all.
Hilarious in Hindsight: In a crossover with Spider-Gwen Miles ends up visiting a universe that's heavily implied to be the DC universe specifically ending up in Metropolis near the Daily Planet. Cut to a year later and Brian Micheal Bendis Miles's creator is writing Superman.
Narm: The Spanglish spouted by Miles' grandma once introduced into the 2016 series.
The concept of Peter Parker having a Legacy Character and an Affirmative Action Legacy is as old as ASM Issue #87, published in the early '70s. In that issue, Peter after going in a depressive funk comes clean to his friends as Spider-Man but on seeing Gwen Stacy's hysterical over-the-top reaction to the idea, Peter decides to make this a Fiction as Cover-Up by asking his former enemy-turned-friend Hobie Brown aka Prowler I, to pose as Spider-Man in his costume. Prowler I had tech that gave him wallcrawling ability and so could pass for Spidey in a limited setting. This was the first time someone other than Peter wore the Spider-Man costume, and the first man to do so was an African-American character. It effect, Aaron Davis, Jefferson, and Miles Morales are Decomposite Character of Prowler I.
Peter's first legitimate Legacy Character was Spider-Man 2099 (which contrary to the whole "100 years in the future" concept and the last two digits giving the wrong impression...was published in 1992). Miguel O'Hara was a Hispanic-Irish Spider-Man in Nueva York, just like Miles is part-Hispanic. The concept of Peter being replaced by a Younger and Hipper alternative was also explored with Ben Reilly in the Clone Saga, while Peter playing a mentor and quasi-parental role was explored in Spider-Girl where he trained his daughter Mayday. Miles' differs on the whole in being a fundamental Setting Update of Peter's classic archetype (teenage Working-Class Hero) unlike Miguel (an older corporate scientist-whistleblower-turned superhero), Ben Reilly (Peter's clone who was young and single as opposed to married Pete), and Mayday (a middle-class daughter to a power couple).
Romantic Plot Tumor: Jefferson is missing, Miles is trying to find him, he falls into another dimension... and we get a lot of romance between him and Spider-Gwen, which comes literally from out of nowhere. It takes some time until the story finally resumes the issue about Jefferson.
They Changed It, Now It Sucks!: In the Ultimate universe, Miles Morales had to endure a lot of stuff, which caused several interesting stories. The death of Peter Parker, his attempt to become the new Spider-Man and gradually be accepted by those close to Parker, the death of his mother, the reveal of his identity to his father, the attempts of J. Jonah Jameson to avoid repeating the mistakes with Parker, the return of Peter Parker and Norman Osbourne, the return of his father and his old history, etc. Then Secret Wars took place, the Ultimate Universe ceases to exist, and Miles is moved to the prime earth. His mother is back and he does not remember anything from the Ultimate Universe, and now he's just The Chew Toy, whose highest problem in life is that his grandmother grounded him or that he has a Loony Fan in YouTube.
They Wasted a Perfectly Good Plot: Miles Morales initially seemed not to remember the Ultimate Marvel universe, or the events of the Secret Wars. After the cosmic retcons, he simply remembers things as if he has always lived in the prime Earth. And his first story in this new context is against a demon, and he gets all freaked out about that, unlike the other heroes who had Seen It All. But in comparison with those things he does not remember, even an actual demon seems like very little for freaking out. He is later on revealed to still remember his home universe, but it's a case of Angst? What Angst?.
Tough Act to Follow: Bendis announced in 2017 that he will be leaving Marvel Comics, and work at DC instead. Whoever writes the comic after him will have some big shoes to fill. However, the eventual announcement of Saladin Ahmed taking over Miles' book in late 2018 was met with approval within fandom.