Microsoft Studios boss Phil Spencer has revealed that the Xbox One version of Minecraft will not be a simple port of the Xbox 360 version. It will feature so many new and improved things, it'll practically be a whole new experience.
And that's why you won't be able to transfer saves from the current-gen console to the next-gen one. When asked by OXM
about cross-gen save transfers, Spencer said, "No, it's a new product on Xbox One. We're actually updating it in pretty significant ways for the new platform. Bigger worlds, which don't translate between the Xbox 360 and the Xbox One."
As for putting Minecraft on Xbox One, Spencer said it was a no-brainer. But, "Obviously this is Mojang's game, and I've had good discussions with Notch [Markus Persson] about where he sees this franchise going, trying to create a more connected Minecraft
world where your creations can go with you from device to device, but I haven't talked to them about where they are on that path."
4J Studios, who works on the Xbox ports, recently said on Twitter
that it is talking to Microsoft about the possibility of save file transfers. Spencer's comments seem to suggest that it's not happening.