It has also been proposed to allow a directional modifier before the brackets. That is, the move within the brackets would always describe the piece with maximum symmetry, and the paths could be classified as orthogonal, diagonal and left-right-handed oblique, the preceding modifiers making selections of those according to the applicable system so a Ship would be v[F?R]. This looks much less contrived than your proposal.
It has also been proposed to allow a directional modifier before the brackets. That is, the move within the brackets would always describe the piece with maximum symmetry, and the paths could be classified as orthogonal, diagonal and left-right-handed oblique, the preceding modifiers making selections of those according to the applicable system so a Ship would be v[F?R]. This looks much less contrived than your proposal.