This is exactly what I was going to post. While luck is a major factor in BABIP, oftentimes, better hitters just have better BABIPs (consistently, over multi-year periods). I think a more effective method would be to look at quality of contact, hard hit percentage, line drive percentage, relative to soft hit percentage, pop up percentage, etc. coming up with a function and finding a way to factor that in. Doing that might help normalize some of the problems you outlined such as overrating low BABIP guys like Gallo