Earlier quoted context omitted.
can you elaborate on what's so terrible about his coding style?
There are lots of problems with it. Here are a couple: He uses poor OpenGL practices, and sees poor performance as a result. He also designed the entire product in a way that makes it cumbersome to mod, without a consistent interface or a logical way for mods to work together. Modding Minecraft as a whole is one big hack. I'm more familiar with the networking side of things. The Minecraft networking protocol is a mes…
Maybe Notch didn't start building it with the idea that anyone would want to mod it. Heck, maybe he didn't even anticipate that it would be popular enough to require great performance. If he expected the game to be played primarily by him and a few friends then he could forego performance for beefier machines.
If he started out trying to build a game that would need to be extremely easy to mod and be performant on millions of machines of varying performance capabilities, he probably wouldn't have gotten around to actually writing it in the first place. It's called over-engineering, and it kills more projects than anything else, IMO.