I have to say, as fun as the movie was, I walked out not feeling any kind of excitement like I got from the first movie. I think this is in large part because the first Avengers movie closed out Phase 1 and went out with a bang. On the other hand, Age of Ultron is just kind of the halfway point to our Thanos Avengers film. As well, Ultron was a self made villain. He didn't rise from some great wrongdoing in his life, nor did he come from another world to wreak havoc. I mean, yay they tie in stuff that will be important in the Avengers movie we're actually waiting for, but at the same time, this came with so little sense of awe. Hell, a lot of it felt like they were trying to emphasize both how essential Hawkeye is for the team, and yet how useless he also is. It almost seems ironic how hard they tried to make him seem important when they later just made jokes out of him once more.
The movie had good action and was otherwise what you've come to expect from a Marvel movie, but it really felt like they were mostly using the movie as an excuse to squeeze in as much character development as they could for the members of the team they have no intention of making a(nother) movie for prior to the big two part Avengers movie still somewhat far off on the horizon.