Salaam Sunwords,
to answer your question, yes and no. I say Muslim fiction is about Muslims, the good, the bad, and the ugly. When I see religious characters being portrayed as the only saviors of the world and everyone else just inherently evil, it comes off as preaching. I've read books written by Muslims that make sure to show the ugly side of the Ummah as well as the beautiful side. The religion is beautiful, but the people are not. There should always be that distinction, IMHO.
Also, for it to be Muslim fiction, or Islamic fiction, I think there should be clear lines drawn. For instance, a Muslim character named Ahmed who doesn't pray, fast, give zakat, and does the complete opposite isn't really Islamic fiction. It would be if there was a concentration on his inner struggle with doing all these and knowing it's against his religion.
But that's just me. I think there can be Islamic literature that falls into other categories.
There's a lot of religious symbolism in Lord of the Rings and its far more apparent in Narnia, even Harry Potter. Same thing goes for Neo in The Matrix (even though that's not literature) Yet not a single one mentions Jesus (A).
Sorry for the long winded response.