(A bit about what sort of stories I like and what sort I end up writing.)
I myself think of fanfic as telling three sorts of stories, each with their own appeal.
Type one is a happy fluffy cuddlly fic that makes the world right for our characters. The road might have some bumps but there's going to be a happy ending, and you can see that from a long way off.
Type two is one where either the ending isn't happy, or the structure of the story is such that the reader (me!) frankly doubts that a happy ending is the obvious conclusion. IMO this is different from the standard quest plot, where the hero goes into darkness on his way to the glorious dawn. If we're always sure that everything is supposed to come out right, then it's not this kind of story.
A third kind is a sort without so much of an arc or journey, but is a description of our Heroes living their lives. I am a glutton for sense detail, and I love this sort of thing. When I'm not paying attention to plot, I think I write a lot of this.
When I am paying attention to plot, I end up with type II fics. I don't do a lot of happy.
Everyone has their own prefs - if we all liked the same things, we'd have a hell of a shortage of beet-and-cabbage soup.
My preferences are for gennish-romance, and for adventures with romance. I think there is more Type one out there than I can read (ie, I like a lot of it, but I don't wnat to read just that.)
I'm not crazy about most AUs and nearly all RPF. I try a lot of things, and many of them don't make them off my hard drive. Sometimes, they don't get past the back of my teeth, and that's okay, too.)
(TWD is the first fandom I've been at all active in for a long time. )