That could have worked. God knows at this point Dick and Cassandra are pretty much on the outs without her being evil. It could have that they had different views on what it meant to be a "Bat". It could have made sense without turning her into a card-carrying villain.
Whatever though I still can't let DC Editorial off the hook, whoever was editing the Bat-books obviously let Beechan's Dragon Lady newly Navajo literate Cass (who now Tim can suddenly beat) through even it didn't mesh with any previous characterization of her. And when it failed, they gave the same guy the mini to clean up his own mess.