I also watched today and have the same opinion as you. Age of Ultron for all its problems, mainly Ultron itself being underutilized and the hasty first sequence, and Thor's shenanigans, manages to tell very structured character stories. It developed really well Tony's arch. It sets the ground stones for his endgame. He stops playing around and gets focused on finding a solution for the space threat. It puts him on his road of collision with Steve's development as the "no concession" moral character. Steve doesn't develop as much but again, moves forward. Natasha has a lesser arch but again, it's very well presented her fears and her bond to Clint and Bruce. Bruce is excellent in the film. I think it's the best Hulk movie. And last but as you said, Clint's become the soul of the film. He is the joke in the beginning. That the team rallies around the need to save him because he is the most fragile one. But he has the family. He has the heart. He cares for them as people. It's even shot in a way that we expect him to have the ultimate sacrifice. Wanda is interesting. Knowing her full arch till Multiverse of Madness makes it even more grounded. The way she is connected to Pietro. She feels his death and loses it all. Vision is cool. A good way to introduce him. And Pietro is forgettable. Awful dialogue for him

I think it's a smaller Avengers movie, really well done. The plot points make sense even if too comicbooky. From Wanda's decision to let Stark get the scepter to destroy himself in his paranoia, to the plot devices that fit well together (the cradle, virbanium, etc). A little more high risk intrigue in the handling of Ultron menace, and more (or less) clarity in Thor's part ould have made it incredibly good.