Doesn't have to be violent, but more mature, definitely. But most important:
HAVE FULL VOICE ACTING.
The fact that they haven't done it already just doesn't make any sense to me.
There's a great reason they haven't done it. Go read Hyrule Historia and you'll find out why.
Cant you just tell us. Please....
The Zelda CD-i games pretty much outright ruined any chance that LoZ would have voice acting. If they tried to put it in far too many longtime fans would relapse to those games. It would be like trying to make a new E.T. game. Even if it was really good too many people would refuse to even touch it because of what happened. --- The enemy of knowledge is ignorance, not religion.
The reason a lot of people dislike a 'more mature' Zelda is because the term has become synonymous with 'Whiny teens/pre-teens who think maturity deals with blood, gore, guns, sex, drugs, cursing, and the like'. However, as should be obvious, this is simply not the case. That doesn't change that people who hear the term are sort of worried that making it 'more mature' will basically turn it into 'God of Zelda XVIII: Hail to the Flag Edition! Now with 'special' Zelda content!' --- The enemy of knowledge is ignorance, not religion.