I had concerns about my previous themes using the built-in Google fonts set of options in the customizer when I read about that court case. However, I had to begin making notes on how to implement changes without causing too much strife for people using my themes.

Careful planning and adjustments are key to making this work, but I believe I can begin the transition with my older themes. I will be starting shortly. At least my latest theme was built with localized fonts; as will all future themes.

One has to consider what will be next; which is a good reason to keep theme (+plugin) feature development to a minimum. Adding too many third-party resources can become a problem later.