Why do sites like this movie so much?

For me, it comes to character. Tony was very elusive in Ironman 2 because he thought he was dying so he just came off as an asshole. Rhodes being replaced by Don Cheadle was not a favorite of mine; he came off much harsher and sterner than Terrance Howard so I wasn't digging him at all. And Hammer was just the most obnoxious and annoying villain. I liked Natasha's introduction into the MCU and I liked Vanko too but the movie just felt a little too bleh for me. I definitely liked the first Iron Man better.

Then they kinda fixed those problems with Ironman 3 for me. Tony came off much more vulnerable. I loved that scene where he tells Pepper that he needs her where he buries his head in her chest; it was the most vulnerable you see him. And Rhodes' character was MUCH better this time around. I enjoyed the part he played in the movie and wish he could have done a little more. I know people hate the Mandarin, I liked the twist. And as for the suits; it was nice to see Tony have to NOT depend on the suits so much; it was a great story about what makes Ironman: the suit or the person in the suit? However, by the end battle, I was kind of over the joke of him not being able to get into ANY suit or every time he got in one, he was forced out the second later. I wanted to see him as Ironman both man and suit at the end. But I can understand why they didn't go that way.

In the end, I think time softened people's 'hatred' of the movie. Not that it was hated in the first place but I remember a lot of people not liking it. But getting to look back on it, I think it grows on people. People understand it more and seeing it in a larger context of the MCU story. I just re-watched it myself on Monday and hadn't seen it since it was originally released on DVD. I thoroughly enjoyed it more than I remember.

IM3 might suffer from being to Shane-Black-ish

Black's great at "wouldn't it be awesome if ..." set-pieces, and this film feels like a series of them strung together by a bare minimum of plot

What if Tony lost his armor?

What if he had only one boot and one glove?

What if he had to executive a mass air rescue?

What if he had an entire army/squadron/legion of suits to command?

I'm not complaining, mind you, but it does make the end product feel like, well, a "product" rather than a compelling narrative

i would say it's mostly because the movie itself is great. one of the best mcu films.

that this has become one of the mcu films it's ok to hate truly baffles me.

it has a funny, clever shane black script, and it actually does the thing so many people complain mcu films don't: it develops and deepens the character & has real heart. people complain about formulaic mcu films, then wail on the film that does the best job of departing from that formula.

that makes no sense!

and it does all that while still having lots of genuinely exciting action moments. the barrel of monkeys scene? one of the best action moments in the mcu.

it's seriously good.

I'm with you Slacker - I think IM2 is great and IM3 is meh for exactly what you listed.