Write what you want to read; I suppose in a way that's the main motivation to write any fic, at least for me. Sure, there's tons of fic in my current main fandom for my current fave ship, but so few of them have the characterization that I want. Which is how I've ended up with the partial outlines and snippets for several fics after about a decade of not writing anything. We'll see if I'll ever complete anything. I remain hopeful.