Based on my own experiences trying to write such things, I've concluded that god game or dungeon master type stories are really hard to write well (and can even be hard to write badly). The basic issue is that there's a lot more planning required than there is for a number of other story types, and a big part of it is how broad the range of things the character can do is.
With many other story types, I've found I can just make stuff up as I go. However, with stories like World Keeper or any Dungeon Master type main character, it's often necessary to do a ton of setting development before anything can really be written. As it is, I've only written one dungeon master type story (failed start on several) and even then I had to cut back their options a ton just to get anywhere with it. The story ended up harder for me to write than other types have been, and I think it came out worse than my other stories did.