K-1 wrote...
What determines worth in people?
It's a very subjective question since...
"What ever may be worth a lot to you is worth shit to me" - Sprite
... but because it is a subjective question that should also mean that the worth of a human being is completely determined by the people around her, right? Then I suppose that as long as you're useful to someone, in some way, you're worth something, and the more useful you are to others the more you're worth? Not a definite answer, just some thoughts of mine.
K-1 wrote...
What makes a person more useful, and what makes a person less useful?
Depends on the task of that person. Worth as a loving father requires love (duh) while worth as a rocket scientist require knowledge in rockets (lol, good example).
K-1 wrote...
... what qualities does mankind need more of, and what qualities does mankind need less of?
Personally, I wouldn't have humanity in any other way. I love our perfectly flawed existance and wishing for more intelligence or more empathy is not only impossible, but it'll also just lead to new problems. Let's work with what we have instead.