Thanks for the post, Justin. I appreciate the long view on WordPress that you present. It's great to see the variety of new paths to theme development being explored. I might even get with a core parent theme if it's rolled out as you've written.

That said, child themes can continue to be helpful, at least for the near terms, to new (to WP) developers, theme houses and for quick builds. Developing child themes can be a great way to learn WordPress theming. I know I did that before I started developing custom themes.

To my mind, the more options available, the better.