I understand your desire to be sensitive.
But a word is not a length of chain with leg irons on it.
Slave is used in many other cases to indicate exactly this kind of realationship.
This reminds me of the recent case where a guy working for the Washington DC used the word "niggardly" in a meeting and was fired for it; the etymology of "niggardly" comes from circa 13th century Middle English and has no relation to "that other N-word."
As a practical matter I don't think slave can be removed. I wouldn't have a problem with aliasing parent->master and child->slave .
