The Plot Was Basically Spider-Man 3
We've already established that The Amazing Spider-Man 2 isn't beneath aping the shittiest superhero film ever, so this isn't a stretch. Spider-Man 3 had (deep breath) three supervillains with coincidental connections to Peter prior to their origins, a Peter-Mary Jane breakup, new revelations concerning Uncle Ben's death, the introduction of Gwen Stacy, and an alien parasite that makes Peter Parker act like MC Skat Kat.
The Amazing Spider-Man 2 had three supervillains with coincidental connections to Peter prior to their origins, a Peter-Gwen breakup, new revelations concerning Peter's parents' deaths, the introduction of Felicia Hardy, PLUS Aunt May's financial problems from Spider-Man 2 and Denis Leary's disapproving ghost dad.
Keeping his streak of stealing from better comics alive.
Because of its overstuffed script, we got crazy transitions like Peter reuniting with his long-lost best friend, Harry Osborn, and them hating each other two scenes later, a calculator inexplicably filled with subway tokens left by Peter's dad, and a plot twist sad enough to fuel an entire sequel resolved in 10 minutes. Of course, this was all basically a 142-minute ad for the upcoming Sinister Six movie.
Look, we don't hate Spider-Man. We want to live in a world where Spider-Man sequels can compete with Dostoevsky and shit. But when you reboot a franchise, forget you rebooted it one movie in, and force Electro to sing his emotions instead of acting, that's not a popcorn flick. That's an evil scheme devised by Doctor Octopus.