I would love a NEW Zelda. Give it high end graphics, a big quest, lots of cool gadgets to use. It would be amazing. The precise control of 2D games simply can't be recreated in a 3D plane. Avoiding enemies, timing attacks, aiming...it is all so much more in the player's control in 2D. 3D makes you need things like z-locking or other computer aided enhancements. Also, 2D allows for real variety in weapons. Things like the boomerang, bow or slingshot could have real different uses and attack styles, unlike in 3D where you simply switch to first person and aim with all of them. Make it happen and take my money, Nintendo!
And that is the big one there. It would be cheaper and quicker to make than 3D Zelda and probably sell more. Especially since it has been so long, nostalga and market hunger would make the audience eat it up. Also, 2D is more accessible. You would potentially greatly expand your Zelda audience. The orignal Zelda was the most complex game to date... but anyone could pick it up and get into stabbing and shooting enemies right away.