I am saying that (for me), Iron Man 3 doesn't make sense as a middle film between Avengers 1 and Age of Ultron. Officially of course it's "canon" but the fact is that if you consider it as part of the big MCU picture it just doesn't make a whole lot of sense.
Iron Man 3 is the only movie which has Tony Stark show some maturity and character growth, try and deal with his control freak issues, and admit and show real vulnerability to the people around him. This Tony Stark,
this guy would totally deserve to be friends with Spider-Man and hang out with him, and IM3 is basically my favorite version of Tony in the movies, and also RDJ's best performance of the character. At the end of IM-3, Tony destroys all his suits and admits that his over-tinkering as a result of PTSD was an attempt to establish control over his life, when he can't always be in control.
Smash cut to Age of Ultron where Tony's talking about building a suit of armor around the world, and was hatching a plan to build a super-AI that automates superhero work and where he basically admits he hasn't gotten over nor is he properly dealing with his PTSD at the end of Avengers 1 when he went to the wormhole. Joss Whedon decided that he wanted Ultron to be the bad guy and that he wanted Tony Stark to be the one who did it, and he basically acts as if Avengers 1 was the last we saw of Tony. So you have a guy undergo severe character regression all for the sake of the larger shared universe. And then they double and triple down on "Tony messing up" for the sake of drama (the Sokovia Accords, tying him into the origins of Vulture, and Mysterio)...and the more they mined that the more anomalous IM-3 feels, and the more Tony Stark comes across as a mood-swinging backsliding jerk who literally can't learn his lesson or change or grow. Like I said...these kind of problems are nothing new in comics with virtually any character but it's especially jarring when you see it transposed to live-action across all these films. Where Shane Black (the writer-director of IM-3) had a vision and understanding of Iron Man (and a kind of satirical edge hence the repeated gag in that movie of Iron Man's suits breaking down, falling apart, and getting destroyed in multiple ways), that was entirely the opposite of where Whedon and later Russo, and Watts, took the character.
These choices weren't inevitable. They didn't have to make Tony the creator of Ultron (because again he wasn't in the comics), they didn't have to make Tony involved in Vulture and Mysterio's origins (because again he wasn't in the comics). There were plenty of alternatives and choices they could have done to maintain the character development from IM-3 in the movies that came after. But the fact that they did, essentially unravelled and undid, and diminished him.