THE GOOD
If there's anything all of us should agree on, it's that the acting in this movie was solid A+ material. Robert Downey Jr., Gwyneth Paltrow, Don Cheadle, Ben Kingsley, Jon Favreau, Ty Simpkins, Guy Pearce, and even the lesser bad-guys Stephanie Szostak and James Badge Dale all nailed their performances. The only one I had any issue with was Rebecca Hall, but she still felt right for the role, and you was disappointed to see her as a bad guy. As far acting, it was actually great.
The movie, while not exactly comic book accurate, was definitely well thought out. The plot, the twist, the theme, the characters--all fresh and developed. Even if you were annoyed by the Mandarin twist and the plot's resemblance to The Incredibles, the main villain Aldrich Killian's motives were understandable and his bitterness relatable. We understood him. We understood the stress Pepper Potts had on her in dealing with Tony, and we understood Tony's stress in coping with the world-changing events of The Avengers.
The case has also been raised that Iron Man 3 was just a cash-grabbing filler movie, and I must argue against this as well. I think it potentially be the strongest connective tissue between the first and second Avengers films, if Joss Whedon handled it that way. Let me explain. IM3 was the first MCU movie to be released after The Avengers. So it had to deal with what just happened in New York as well as laying the groundwork for the future. Stark was used to being the big gun, and now he's not anymore. What was it he told Pepper? "There are gods and aliens, I'm just a man in a can." It's this realization that haunts him, and through their exploration in Stark's PTSD we delve deeper into his character, and I loved it. Not only that, but we see the government's reaction to the events of The Avengers by rebranding War Machine as Iron Patriot, who will be their hero sent on different missions. But it also planted seeds such Iron Legion and President Ellis. We will see a new version of Iron Legion in Age of Ultron, and I'm sure we'll see Ellis again sometime in the future. Most importantly was the overall theme of the movie: "We create our own demons." I hope this theme carries over in to AOU, as it is Stark himself who creates Ultron.
THE BAD
The humor and Mandarin twist themselves wasn't what bothered me; what bothered me is that it wasn't what it paraded itself to be. The trailers for the film made it seem like it was going to be a darker take on the Invincible Iron Man; what we got was an action-comedy. I am perfectly fine with action-comedies. But I was in the mind-set of something more Nolan-esque. It was also assumed that the Mandarin was going to have ties to the Ten Rings terrorist group that plagued Stark in the first Iron Man film. But although they're mentioned, they didn't have a presence whatsoever in the movie, and that was disappointing.
Another thing that bothered me is that it wasted a few characters. Ashley Hamilton and James Badge Dale portray Jack Taggart and Eric Savin, respectively. In the comics, Taggart and Savin were Firepower and Coldblood, two minor Iron Man villains. Coldblood is of more interest because he's a cyborg. Since they are minor villains, it's easy to excuse, but I don't know why they didn't just use original characters for Extremis henchmen. I mean, Jack Taggart was barely in the movie at all, and they could have used his character for later movies.
And the most minor thing of all was what bothered me the most. At the end, Stark orders J.A.R.V.I.S. to activate the "Clean Slate Protocol," which blew up all of his suits. This was an effort to show Pepper that he will be focusing on her from now on, without other distractions. However, this just didn't feel right to me. I get what he was trying to do. But theme is that he created a demon in Killian, which came back to haunt him. As a weapons dealer, you know he created other demons, and that there will be other threats to him and Pepper. If not for his "distractions," they would have surely been defeated. So blowing them up didn't make sense to me. After all, they're already built, he could easily say that he's going to let either J.A.R.V.I.S. or Rhodey take over for a while, or SOMETHING of the like. Also, we know there will be another Iron Legion in Age of Ultron, and it would have felt more connected to me if they had used the same Iron Legion.
WHY IT WASN'T UGLY
While I definitely would have done things at least a little differently, Iron Man 3 was an enjoyable film. No, it wasn't accurate to the comics, but it fit well with the MCU, it had funny one-liners and awesome action scenes. That's all I want from an Iron Man movie, man. I mean, people get so caught up in what they don't like that they forget all the cool things that came with it. All the different, badass suits, the cool Stark escape scene, the Bruce Banner cameo. It was entertainment, and damn good entertainment if I do say so myself.