FWIW, this is basically zenchess.com and cluechess.com
I think compare of attacking potentional is needed to be addicted to gaining benefit in position , winning a piece or being closer to mate.That 3 goals can be described with different weights , that can cross each other in some ways. So to create these weights, we can't without real calculation of position. But we may check branches that are near these 3 goals and describe piece activity according to these branches. I myself think that piece activcty should be calculated relative to branches , that in the end are giving benefit to one or the other side, because that only piece activity is needed for, so by giving weights to piece activity according to closest benefit branch for one side or the other..Also deviation from one branch can create new one, and by such process we fill all weights for piece activity by filling branch variation. Such scheme can create field of weights of piece activity., if we fill all branches to some depth of calculation