Yeah but each family can have X number of objects which have an variable called the same but with a different default value.
If you make an instance of an object it should get the default values of its parent.
object A: I = 10
object B: I = 15
and are in the same family.
so if you make an instance of object A as far as i know, it should inheritance its I value.
So if you change object A I value, newly created children of that object should get that value as well.
As far as i see it, its no different in construct 2, there is just not a function that allows you to specify what "family member" you want to create.
But i might be wrong, but i cant see why there should be a problem in changing a parent object default value, just because its part of a family.