Sorry I haven't visited the forum in a while...
Optimize for Reading seems to solve my problem in this area. I don't think I've ever started an episode playing when I meant to download it, but I have often started an episode playing when I wanted to read the episode notes. This illustrates that settings are a disease. All these user choices are not a substitute for a coherent predictable design.
Playing with Optimize for reading just now reminded me of how much I dislike the little popup that's used to show episode notes from the Now Playing screen. Wouldn't life be easier if there were only one view for showing episode notes?