A companion could be very helpful in this game. They could help you explore the vast terrain and tell you useful hints. I for one think companions are useful, and they really can have a great impact on the game story-wise, like Midna did, if that's the angle they go for. Remember, Link is silent (I hope that never changes), and information needs to be conveyed to the player and NPCs. I'd rather have a character do it than generic text boxes. It makes the game unique and adds depth. Plus, Midna and Navi are very interesting and popular in the Zelda fanbase.. KoRL is an enjoyable and helpful friend. Fi is annoying to many, but is still memorable in her own robotic way.
Give me a companion Zelda U!