Notch never bothered seriously with MC after he cashed in Alpha and early Beta. The community carried MC into the success and Notch was cool with this (see the endless mods and such). Because the basic Minecraft versions never offered anything interesting. The mods did.
Right now he discovered that he don't want to deal any more with the drama and thus cashed a little more money. Technically he never has to work any more in his entire life. So he can just go do random things here and there (cash more money) with easy life.
But hey, nothing to blame him. He pulled a smart move and I would've done the same.
Microsoft doesn't needs to do much about MC since the community still carries the game. Maybe rewrite it in VISUAL BASIC or something to ditch the **** Java, but probably that will anger modders here and there.
Never having to work again is at about $1M (most people work because they like it, or waste money), he's at his grandkids never have to work level.
If you're going to rewrite it needs to be C++, due to multiplatform.
Java's hate is mostly for applets (equivalent to MSs ActiveX) , not for standalone programs like Minecraft.
Java's main problem especially Java64 is the RAM overhead.