While I do feel a lot of features get started and then left pretty much unfinished or totally undocumented, I mean you get what you get. I’m sure the devs don’t get to choose what they are assigned to work on. And for the most part they are really awesome and helpful (like Nick Darnell who used his personal time to write code so we can use gamepads in UMG, or Mieszko who has probably replied to every AnswerHub question I have seen regarding AI).
There are going to be the same kinds of issues, whether it’s Unity, CryEngine, Lumberyard, or even Reality Factory/Genesis3D.