I really hope it doesn't mean much to "Minecraft" as we know it. The game is essentially "done". They might continue yearly content updates (Yes, Mojang only released 1 update this year, 1.8... and it seems likely to be the only one). I don't think they're really interested in selling it currently as a game, so much as the name "Minecraft"... and future titles and marketing, etc. Of course we'll see super pretty versions for xbox... probably exclusively for months after release. Think of EA's buyout of Plants vs. Zombies becoming PvZ: Garden Warfare... if you want an example.
One of the original draws to minecraft for me was that it was a bit grassroots, and had that independent feel. It felt very 'Open source', you could make mods, run servers, etc. I have a feeling minecraft 1 will be the last one like that.
As for Notch... I think he hates the persona he's become. He's just a guy who likes to mess around, do some programming, stay up late... and he became a bit of a star... arguably that was his own fault, but I can't help but feel a little sorry for him. He pretty much killed 0x010c because people were expecting it; wanting it to be an EA title, and really he just wanted to mess around with a fps, with maybe some computers thrown in. Some people can handle stardom, others can't. Still, I hope he can cry himself to sleep with his 2.5 billion.

He deserves the holiday.
Some fun math... the breaking bad
'money bed' is estimated to contain about 50 million in various denominations... so imagine 500 of those... that's about how much money Mojang has now.