I create a family, add one variable to this family and include an object in this family. If this object has 50 variables, when you assign the family to an empty object, construct forces you to apply 51 variables, when I really want the family expecific one. If I check only the original one and uncheck the other 50, construct gives me this warning: "All events referring to the unselected family variables will be removed". The problem is, when you assign a family to a object, this family absorbs all the variables that alredy exits, so somehow it loses the family sense and don�t has family expecific private variables, forcing you to share all of them.
Then if you want remove families and variables... it is a chaos, because you have dependencies everywhere.