I try to avoid watching him. It's enough to read his mumblings recited in articles to Keep up with the insanity; the sound of his voice, otoh, is something I spare myself.

You don't need to be familiar with The Good Wife to follow The Good Fight, all the necessary info on crossover characters is provided within the show itself. Though my guess is that without knowing her as a fascinating supporting character from past seasons, someone like Diane might feel different for a new watcher.