As a new user who's shopped around RPG forums a bit, my only issue with broad genre subsections is that it proved to waste a lot of my time, as I'd say go check a section such as Fantasy only to realize that most of the RPs were what people here would call Free level and that's not my preferred type of play-by-post.

Another balance is also just the number of subsections, too few and it's not specific enough, too many and it feels like you have to click forever to check if there are any new interesting games.

Ultimately, I have simply changed my approach to simply focus on the what the pitch is, the history of the DM/GM by checking what they've done before, and seeing how things pan out in terms of characters people submit as there is so much variability even within the same writing level subsections that the broad target for each subsection is fairly meaningless as an indicator of what to expect unless you are jumping up or down two levels.