Notch gave the world a fun game, you gave him a small purchase price in order to enjoy it, end of transaction. The fact that he published thoughts and future plans does indenture him as your eternal entertainment provider. He should be free to leave daily development and do with his creation as he will, including deciding to do something differently than he originally envisioned. This is his prerogative as creator. To all the people who claim their participation "made" the success of Minecraft, I say bullshit, you are playing a fucking game.
You know what's a lot worse for humanity? When Twitter decided to be a media company instead of an infrastructure company. That also pissed off a lot of people who "made" the success of the company. But you know what? Same deal. It's their prerogative. You can cry and gnash your teeth, and of course you are entitled to your opinion, but the value of all those opinions? Farts in the wind.