To be honest, it seems like all Notch has been interested in lately is soaking up publicity rather than working on his fucking game.
I still enjoy the game and am glad I bought it but there is still so much untapped potential in the concept and it would be nice to see it come to fruition. If he has no interest in improving the gameplay in any way, the least he could do is make a friendly mod system so others can do it. The community has already come through and developed a ridiculous number of mods, but I'm hesitant to use any of them because most of them make permanent alterations to your world (custom block IDs, etc.) that can make a map unplayable if the mod is ever removed or, more likely, loses compatibility due to an update.
Really, I'm wondering why modding hasn't been given more of a priority in the game's development thus far. Texture pack support was put in but that's basically it. Why no mod support??