Sure, there are a couple of lesser films, but all of them were worth watching, and all of them tied into the final, amazing culmination that is Avengers: Endgame. This was also a series that I felt got better with time. While two of my top movies are in Phase II, every Phase III movie showed that Marvel (and Disney) have been continually raising the bar. Honestly, I don't know how they could ever top the Infinity War-Endgame duo. I think that they will have to go with smaller movies for a while before trying something like that again.
I don't think that I would structure any future marathons quite the same way. While three movies was a good amount to take in on a given day, the stretched out format ended up feeling a bit disconnected by the end. I also made the mistake of putting them on Wednesdays; unintentionally creating a conflict with Wednesdays in the Park. Thursdays would have probably been a better choice.
All-in-all, it was a fun experience that helped to show the interweaving threads which bind these twenty-two movies together.