Iron Man 3 definitely has it's problems, but it was still good on it's own for the most part. There were many cool scenes like when Iron Man saves all of those people who fell out of a plane, and the climax in this film was much better than the one from the second film. The fake Mandarin was something I didn't like since the fake videos of him made him look really threatening and cool, but when it's revealed that it was all bogus that really wrecked the villain of the movie. Also, the whole thing of Tony having nervous breakdowns because of the the events of The Avengers were interesting since he's seeing how big the universe is, and how small he is compared to the entire universe which causes him to have nervous breakdowns. Also, the bond Tony makes with that kid was nice to see. Not one of the top 10 MCU films at all, but still fine on it's own. It does have flaws though.
In regards to Avengers: Age of Ultron I thought it had good ideas, but I'm in full agreement that it feels like too much was put into it. Ultron is a compelling villain especially since he doesn't try to present himself as a villain. I thought it was neat how he feels he has all of the answers, and that he just wants others to get him. I know he has violent outbursts, and I thought his reactions after his outbursts were done in a way where he pretty much says "No, I didn't mean it that way. I just want you to get where I'm coming from".
In regards to what I would consider my absolute favorite MCU films these are pretty much the ones I liked the most.
Captain America: Civil War
Iron Man Thor: Ragnorok Black Panther
Captain America: The Winter Soldier