Ah...the old "run prevention" theory again. How did that work out a couple of years ago for us when Theo signed Mike Cameron to defend against runs? Nonsense. Ever read "Moneyball"? The data Billy Beane used to create all those winning teams disregarded "run prevention" and still managed to win 95+ games a year until everyone else caught on to those theories too. Jose Iglesias has played 10 games for the Red Sox and in your mind he is already Ozzie Smith. Talk about rose colored glasses....
I realize this is way over your head to comprehend, but at least I am making an effort to explain it to you, right?
As for being a talent evaluator, yes, I do think I could do it with the proper training and access to data. Its largely an educated guess anyway, a calculated crapshoot. Professionals can be wrong, and frequently are wrong. If your doctor tells you to drink a glass of hemlock to cure your acne, are you going to do it or are you going to question him? How about if he tells you to take echinacea for your cold?
Learn to think for yourself. It will be a very liberating feeling for you.