Why can't we use static objects?

My personal choice would be to NOT include authentication with CI.  I think it is better left as a third-party tool to be integrated by the developer.  This avoids "code-bloat", which we see in competing frameworks.

Why not? proper implementation cant be bad, where-areas many developer (beginners) are using very poor auth system and also many devs just stopped using CI.

namespaces are very desirable in CI 4.0, even if it mean CI becomes more complicated for the first-time user.

well, first-time user this days learn Laravel or Symphony or Yii :=D