I've had a minecraft server running for a while, for me and a few of my friends. I'd say it's perfectly playable and fun for the purpose we've used it for; lego style building.
We've built so much and created so many cool things that we could never create in any other game, with such ease.
The survival aspects of survival mode are merely annoyances that we conquered quickly after estabilishing a "base".
What does the game cost these days? 15 bucks? I've had more fun in minecraft, than 15 dollars could buy me in 90% of all other games on the market.
As to him selling the data, the point was that he can use the data for whatever he wants, as long as the result is an improved minecraft. But optional would be good as well.