Zelda already has a huge fan girl following. I know, all my friends (who are girls) and I are hardcore Zelda fans. My aunt once called Zelda a girly game...though I find that offensive. xD Nintendo new pholisophy is that they need to stop focusing on a small group and try to do things that would welcome new people.
Just look at this the Wii has tons of players and yet only a small percent of those people play Zelda. I don't think this has to do with casualizing or feminizing everything...just make a wider appeal.