First, let's talk Tobey Maguire versus Andrew Garfield. Everyone told me Garfield is so much more convincing as nerdy Peter Parker . . . but I don't see it. The first time we see Garfield's Peter in school, he's got perfectly puffed hair, contacts, a skateboard, and a hoodie. He stands tall. He looks cool. The first time we see Maguire's Peter, he's chasing after a bus and being laughed at because his clothes and glasses may not totally hide that Maguire is a movie star, but he's at least acting lame.
The girls are pretty even. Emma Stone is perfect for Gwen Stacy; Kirsten Dunst is a perfect Mary Jane Watson. But the thin ponytail and thick bangs that are Stacy's expected look are terrible for Stone. She looked best in the scenes where they let her hair be down and wavy - they should've just let her look nice instead of trying to conform to strongly to the comics look.
And look, I love Sally Field and Michael Douglas. But they were terrible as Aunt May and Uncle Ben. Douglas's Ben was a scold and Field's May was a doormat. And look, Aunt May might be old, but that woman is firm. She's one of the best parents in any comic book universe, not a woman with no control over her household.
I'm not even going to bring up direction. Sam Raimi crushes Marc Webb. Webb's scenes of Peter slinging through the city look like everything that's been done before. Raimi's felt fun.
As for mythology choices, I understand that The Amazing Spider-Man wanted to be different from Spider-Man. People have complained for years about Peter's web-shooters being organic, so making them once more his invention could've been a good move. But the organic webbing simplified the story in Spider-Man. The large order of Oscorp webbing had to look suspicious. And it just felt wrong without Uncle Ben saying, "With great power comes great responsibility." Maybe they could've had him say the original "With great power there must also come -- great responsibility!" instead of dancing around it?
Plot-wise, I liked that Peter was a little more free with his secret identity. Keeping it super secret damaged his relationships in the original movie trilogy. But there has to be a happy medium - I felt like almost every character knew who Spider-Man really was by the end of the film. Saving Norman Osborn for a later movie was probably a good move - it helps differentiate the movies and allows for a bigger, more recognizable bad guy to come along in a later entry in the series. But Rhys Ifans, who I usually find hilarious, wasn't the best fit for the villain. Perhaps no one would be because the guy is just that grating. Osborn at least has some charisma, and Willem Defoe did an amazing job of playing two personalities. (And props again to Raimi, for the framing in the scenes where Osborn talks to himself as the Green Goblin.)
Others might disagree with my opinion, but here it is. The Amazing Spider-Man was a decent spectacle and hit the standard comic film beats that I love. However, Spider-Man is a classic of the genre, and its successor didn't come close to touching its highs.