It can still be freely chosen whether the Joker would mimic the last-moved piece of the opponent, or the last-moved piece period. The rules could have been such that the black Knight move switches both Jokers to Knights, instead of just the black one. This is just a different kind of imitator.
Hmmm... The second option would be slightly easier to implement because it's closer to how it is currently written. It also might be easier to understand -- maybe. But I have no strong opinion either way.
Hmmm... The second option would be slightly easier to implement because it's closer to how it is currently written. It also might be easier to understand -- maybe. But I have no strong opinion either way.