i don't use these so i can't comment specifically. before player roles i had tried to settle on linear formulas for player rankings, and was unsatisfied, so haven't touched player roles but have went through the same thing. i think its roughly impossible to build a highly accurate linear formula to evaluate a player. but you can get a useful benchmark, help separate the wheat from the chaff.
so i think the right goal for player roles is just to get a good ballpark figure, and to still be doing the important evaluations with the eye test. and in light of that, its not really the kind of thing where there's a right answer, although i suppose there are probably plenty of wrong ones?