Khris, just a thought.
Those attacking-minded players (eg. AML/ML/DL with SA like shadow striker) could be competing as a scorer against a classic CD, and that would be very unfair (Wingers scoring twice can already easily outscore any defender in a match on ratings, hence motm). Also some player combinations like AMC/MC/DCM with freekick as SA.
Suppose most top players would be multi-positions, and to strike a balance, maybe it’s fairer to at least exclude all players with AML/AMC/AMR positions? Midfielders do assist and score in matches, but then defenders do with right formation and tactics.