Personally, I think Phase IV should bring more morally oriented stories. I mean issues that are not just about villain who wants to either controll, destroy or take some kind of revenge on something and the acting heroes in order to maintain the status quo. They should instead go for plots that explore more than two sides of the story and allow the spectator to choose the side.
They should also consider making villains last as they do with heroes. After all, with the exception of Loki, all other villains were somewhat one-dimensional. Marvel has many great villains that should not be killed in the first movie the appear, and if heroes can team up as Avengers, why can not there be Masters of Evil or Intelligencia?