(Not the anon, but curious regardless) If you did do a Gym Leaders series, you could do it like the anime and do two or three Gym Leaders at once, united by element or theme or region, and you could definitely talk about their anime incarnations at the same time. That way we could get your opinion on Leaders and their Gyms in nice little packets and if there did turn out to be ones who you find yourself with a lot to say about, they could have their own posts.
Hmm. Well, to be honest the likelihood of me doing this at any point in the near-to-medium future is slim to none, but if I ever find myself wanting ideas, I’ll bear that in mind. Could be interesting to take it as a way of doing a thematic look at different types.