I wonder if we could even throw in encapsulation? Eg. variables only accessible by the object that owns them. Would that be useful in the real world? And polymorphism...
Well for once, you wouldn't be able to pick which family variables go in and which not (that in itself is weird to me). All vars from the family go in. When defining the family you would have to decide which variables (attributes) it has and their default values. These could be changed without having to touch the objects inside that family.
Encapsulation could be in the form that you could define an attribute (aka family variable) as private, and it wouldn't be accesible unless you were refering to the object via its family. Protected doesn't make sense in this context, as Construct's "methods" (behaviors) cannot read from other objects... can they?
Polymorphism... mmmm well for inheritance you could add families as members of other families, that would be nice. For polymorphism you'd have a family or object that's a member of several families (which is possible right now). What to do with an object that belongs to several families that have attributes with the same name? I'd say just forbid it and show a warning. It's a nightmare in any other way.
PS: I tried the familysubevents.cap but it's saved in a newer version and I'm not updating until I finish my current game =)