Fascinating post. Regarding the 2 "important points" in the comment, they reminded me of a brief but brilliant, thought-provoking quote by the philosopher Ken Wilber. He once stated something to the effect, "From amoeba to man, from man to what?"
Another time, Wilber wrote, "If man and woman have come up from amoebas, then they are ultimately on their way to God." (Although I prefer to use the term "divinity," which does not have all the baggage of terms such as "god" or "allah" or "krishna.")
Looked at in that light, there's plenty of room for improvement and lots of time for improvement. Like, a few billion years.
Implicit in Wilber's thought is the understanding that man is not the be-all and end-all of evolution. To assume that we have evolved this far (from amoeba) and that's the end of evolution is absurd.
Another point to consider is the fact that (our) evolution is speeding up. Of course, there are plenty of obstacles, there are many factors holding us back, and there will be plenty of regression (devolution). But a cursory look at any history makes it quite clear that our evolution is becoming increasingly rapid.
Onwards, and full steem ahead. (pun unintended)
RE: Is biological evolution a ball rolling up a hill all by itself?