I think it's not difficult to know who the top guys are. I look at it more as an exercise in probability. It's not a coincidence that the blue blood programs seem to target the same guys. There is certainly a correlation between a history of high end productivity at the P5 level and the probability of success going forward. Similarly, there is a correlation for players at any level with elite numbers in one or more area (scoring, shooting, rebounding, shot blocking) and analytical data support (Bayesian Performance Rating, eFG%, TS%, USG%).
Those are the top guys. Teams are paying up for the higher correlation. That's why those large deals are made. Will there be exceptions? Yes, there always are. And this is true no matter what you are measuring. But, exceptions to the correlation do not disprove the correlation.
So...could Allenspach be the better player as compared to Estrella? Yup. But, Estrella was the better bet.