I might say that Notch is the best kind of coder, for what his goals are. Notch is, really, a game designer. The goal of a game designer is to iterate a set of rules and mechanics until something fun is tracked down ("fun" is sort of the "product-market fit" of game development.) in the process, they may create prototypes that allow them, or others, to play-test the rules/mechanics, but that prototype is not the output product of the game-designer's work, the ruleset itself is.

Now, frequently, a game-designer may also be a game-developer (someone who takes a ruleset that's already known to be fun, and builds a solid game engine to enshrine its behaviors), and a game UX designer besides. But this doesn't have to be the case. Miyamoto doesn't code or do UX. Will Wright doesn't code or do UX. And Notch should be in roughly the same category.

Obviously, there might be some dysfunction at Mojang that results in prototypes getting shipped instead of developed—but that's a separate issue.