Notch is a nice guy, but as people have said, Minecraft was a once off.. he struck it extremely lucky.
As for future games, he'll always be limited as long as he uses Java. He'll be stuck making these small nimble games as that's what he is limited to.
He doesn't care, he's got enough money to do what he wants. He just enjoys writing games.
Have you seen RuneScape? That's probably the biggest game that uses Java and is by no means a "small nimble game". Sure it isn't one of the best games out there but it is quite impressive what it has accomplished using Java, not to mention it is all browser based.