It's not being released as a replacement for a new Zelda game - they've already said there's a new 3D Zelda game in the works for the 3DS.
As for wasting resources - minimal resources are being used to take an established developer and help bring them up to AAA-Title Nintendo standards. That doesn't sound like a waste to me. Could they have done the same thing with a new title? Sure - but it would have taken a lot longer and a lot more resources.
Take an existing title, show them "The Nintendo Touch", teach them how to use it, then, let them try something that allows them to have a bit more freedom.