Really good post...it makes a point that is completely new to me, which is always nice.

It does occur to me that the current (negative selection) system would reward "hard work" more, relative to "talent", than a positive selection system. (In quotation marks because those are both metrics that are hard to measure separately from one another.) Someone who is very conscientious and hard-working is likely to compensate for wherever areas they're weaker, in terms of "natural talent", however you define that.

My first, emotional reaction to your post was "I would be screwed in a positive selection system!" As someone who's above average in a lot of areas, not really exceptional in any, and obsessively hard-working enough that it's a running joke among my friends, I like the current system just fine (although I'm not in academia.) I don't know if conscientiousness would have a bigger long-term effect on results than innate brilliance; it probably depends on what field you're talking about.

My intuition says that a positive selection system would probably be a good idea in fields where there is big variance in natural ability, i.e. math or physics, and less so in fields like medicine where a lot of "talent" depends on how willing you are to work hard and keep improving over your whole career.