(just translanted the rules to dutch so i started to think about them :))
would it be a nice variation if a player would place 1 piece of a 3rd color .. (grey) which would turn all enclosed pieces into the other color. When the move is completed and the pieces have been turned, then the grey piece changes into the color of the player who made the move.
so it would act as both a white as well as a black piece .. turning the black pieces which it encloses with a white piece on the other side and turning the white pieces with a black piece on the other side as well