Did you also notice how the need for interface and type abstractions goes away? If you have a function that sum()'s a list of numbers, you can use that to sum() any of the Ant's members by passing a ref to the list. Otherwise you have to write AntSummer classes that take Ant (and all the children of Ant's class).

It does occur to me that there's a certain type of programmer for whom this is obvious. And that type of programmer was not using classes anyway for the reasons above. For that programmer, objects are a massively overused hammer in software design. I know those types, and they're very good. It might be there's too much brainpower wasted in designing object hierarchies that could go to exploring functionality or producing value. Or it might be coincidence.

I'm not really that guy necessarily, but for simply reasons of communicating and comprehending designs I always thought objects more than a few members were just plain wasteful. There just never seemed to be a reason to have all those mutable hidden member variables unless it was to abstract something like a data structure.