Hey, Fandom!
I'm a predominately story-driven writer as well, and I agree it's a hassle to find like-minded partners here who are invested more in the story than how soon characters get naked. While this is an adult site where many if not most writers are coming for the smut-focused content, personally, I'm here to write stories with some sexual content, plus other themes that would fly way over a PG-13 rating. Romance and smut are only facets of my stories just like drama, adventure and conflict. All parts of a greater whole to drive the plot.
Honestly it's really a matter of sticking it out, in my experience. I put up notes/reminders in my request thread, journals, etc, to clarify what I'm looking for, and ultimately it's up to the reader to actually bother, well... reading that. I still receive a number of PMs from writers who haven't taken my preferences into consideration. It can be a frustrating slog through a dozen messages of which maybe one or two people actually want to talk plot, yet there are most assuredly writers who enjoy basking in several pages of plot and character development before things get spicy, if at all. I've found several fantastic writers (and friends!) who put story first. It just takes a bit of weeding through the messages and RTs. So please don't get too disheartened by the content you see a lot of - it's the nature of the site but there are diamonds in the rough here.
Rather than the suggestion of making new boards for story heavy content - I truly don't think a completely non-adult board would fly here - what about a registry for members who are story first? I can't put a ratio on it (and honestly I hate those ratios because stories are so flexible) though maybe a quick description of what's meant by story-driven and then a list of players with links to their RTs and such.
Edit: fixed some grammar. Also couldn't find another proposed registry list.