I don't know, I think some improved hardware would greatly improve the aesthetics of the Lost Woods, which severely drops in frame rate when docked. Handheld, the diminished fidelity at 720p buys back some frames.

I'd be inclined to agree about some older Zelda games though, namely Wind Waker. I replayed it on GCN recently, and can attest that HD Wii U version really didn't add anything to the aesthetics.