1) It looks dodgy.. the speeded up video of making a basic hut has be worried.. doesn't fill me with confidence of the interface.
2) Some people have serious problems with sitting on their asses for days on end playing minecraft non stop. This will only allow them to play when they need to go on the toilet.
In a perfect world this would let them go out.. meet some nice girls and boys in the real world while still playing... still, its wrong.
I'm just afraid of minecraft becomming the new World of Warcraft were people lock themselves away from the real world to play. Sadness, and reflects badly socially for normal gamers who play.
3) Minecraft isn't a mobile game... as you idealy need a decent screen to play as its a WORLD based game that requires alot of time to play and mine...time is something mobile devices arn't good at due to connection costs and battery life. I would have thought a basic minecraft client for phones so players can log into their servers to do basic maintaince things would be great...but for actually playing outright only on a phone... don't think it would work.
Personally if anything I feel this should be aimed at tablets and not phones, Minecraft has evolved from a basic Java game, but meh.. I think a version of minecraft for console players (xbox and ps3 - not the wii as we all know thats aimed at stupid parents with stupid children) should come before a mobile port of the game.