One thing I do appreciate about the classes in this series is the sidebar lectures on important things a game designer ought to know (such as this topic as well as the debugger lessons). Even if they are not necessary for basic RPG development.
I recently watched a training video for an external asset pack I downloaded. The lecturer made a good point that we can use the override technique to avoid having to change the original asset code to make it work in our own game. A separate subclass can modify the parts we want in the parent class with a completely separate file. Just another thought as we talked about in this lecture as it being a technique for customizing a subclass.