Well...
Now we know what Microsoft plan to do with Minecraft. Nothing.
With everyone wondering if they would change the engine from Java; possibly shut down Linux gamers, all the plug in thing that's going on ... I have to admit that I didn't see this coming. Let it languish and start up something else.
Got to admit that it will be interesting to see the "openness" of the new title; plug ins (which never really did, "happen" properly after the bukkit staff went over, IMHO) and whether they will come down on social media footage of game play, or animated stories of the world (does anyone actually know what became of the very last episode of the "Eggs explanation of Minecraft" from Element Animation?)
And, of course, the speed/discussion/forum control ... of the existing community and whether there will be any further progress to be made to the Minecraft game itself. (which I doubt)
Thinking on this, it probably isn't surprising. The existing assets are so open that they would probably be too difficult to monetise now, so this announcement probably isn't that much of a shock really.