Yerm on 06 December 2017
Zelda definitely could, but it doesnt really need to. Breath of the Wild might not have blood, gore, or vulgar language, but i would still call it a mature game. It requires a lot of thinking and quick reflexes if you want to avoid dying too much, which is what I would expect from a game targeted at an older audience.
Metroid however could really shine with a higher rating. It deals with bounty hunters, intergalactic parasites, the main villain in the game is a giant demon-like dragon. If they made an M-rated Metroid game and had the privilege of dialing up the gore and possibly even horror aspects of the game, I think people would be thrilled
