Ultra mature? I'm not even sure i know what that means.
If you mean more complex and sophisticated character interation, sure, but If you mean Link is going to be ripping off heads and disemboweling people then no. The stakes in any Zelda game are enough that there is no need to glorify or play up the violence, if you did it wouldn't be Zelda.
I don't mind Zelda being dark but honestly I wouldn't want anything darker than Majoras's Mask which has a very unsettling atmosphere at times.







