The example is not quite good, since FT is about the only skill which works by itself, and not relative to other skills. So a rise of, say Rebounding, by 1 level is only meaningful if the opposition is exactly identical. Otherwise, you should be looking at the difference in skill levels between your team and your opponent.
That doesn't mean you can't still have this discussion, just in another way. For example, if I give you levels of player vs player for inside shot vs inside d.
-Is it better to be tremendous vs sensational OR inept vs awful (both 1 level difference of skill)?
Also, one model for stamina could see it working similar to FTs. By this, I mean that a player will tire at x speed with atrocious stamina but y speed with respectable stamina. Is the progression linear for each level up of stamina? Or non-linear like it is for free throws?
Run of the Mill Canadian Manager