I sort of wonder if Hickman took Avengers as a way of getting to tell his larger story. His FF run sort of climaxed 6 months before he left. He used his last months to tell one off stories, wrap up a few loose character arc ends, and set up Black Panther. However, I remember thinking at the time that it sort of felt like Hickman was killing time (even if the stories were still good) as opposed to wrapping up his 3 year run (which was more or less done the previous April or May). Then post AVX, he takes over Bendis' Avengers titles. New Avengers was clearly the continuation of his Fantastic Four stuff. Avengers was sort of just there for awhile. Things improved some during infinity, and got a lot better post-time skip, but it did feel like Hickman did Avengers so that he could write New Avengers (and ultimately Secret Wars). We got some character progression out of Sunspot, and a new take on AIM, but that run was definitely weaker than FF, New Avengers, or Secret Wars.